US20240170218A1 - Multilayer ceramic electronic component - Google Patents
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- US20240170218A1 US20240170218A1 US18/422,421 US202418422421A US2024170218A1 US 20240170218 A1 US20240170218 A1 US 20240170218A1 US 202418422421 A US202418422421 A US 202418422421A US 2024170218 A1 US2024170218 A1 US 2024170218A1
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- 239000002184 metal Substances 0.000 claims abstract description 160
- 229910052751 metal Inorganic materials 0.000 claims abstract description 160
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- VCUFZILGIRCDQQ-KRWDZBQOSA-N N-[[(5S)-2-oxo-3-(2-oxo-3H-1,3-benzoxazol-6-yl)-1,3-oxazolidin-5-yl]methyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C1O[C@H](CN1C1=CC2=C(NC(O2)=O)C=C1)CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F VCUFZILGIRCDQQ-KRWDZBQOSA-N 0.000 description 1
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Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/228—Terminals
- H01G4/248—Terminals the terminals embracing or surrounding the capacitive element, e.g. caps
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/005—Electrodes
- H01G4/008—Selection of materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/005—Electrodes
- H01G4/012—Form of non-self-supporting electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/018—Dielectrics
- H01G4/06—Solid dielectrics
- H01G4/08—Inorganic dielectrics
- H01G4/12—Ceramic dielectrics
- H01G4/1209—Ceramic dielectrics characterised by the ceramic dielectric material
- H01G4/1218—Ceramic dielectrics characterised by the ceramic dielectric material based on titanium oxides or titanates
- H01G4/1227—Ceramic dielectrics characterised by the ceramic dielectric material based on titanium oxides or titanates based on alkaline earth titanates
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/228—Terminals
- H01G4/232—Terminals electrically connecting two or more layers of a stacked or rolled capacitor
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/30—Stacked capacitors
Definitions
- the present invention relates to a multilayer ceramic electronic component.
- multilayer ceramic electronic components represented by multilayer ceramic capacitors have been increasingly used in more severe environments than conventional environments.
- the proposed multilayer ceramic capacitor prevents formation of gaps between a ceramic body and an external electrode to thereby improve the adhesiveness between the external electrode and the ceramic body.
- Japanese Patent Laid-Open No. 05-003134 discloses a technique for using an electrically conductive paste for an external electrode connected to internal electrodes stacked inside a multilayer ceramic capacitor.
- ceramic powder forming a ferroelectric ceramic layer for the multilayer ceramic capacitor is dispersed as a coexisting material.
- the multilayer ceramic capacitor disclosed in Japanese Patent Laid-Open No. 05-003134 causes the following problems. Specifically, when an external electrode contains an electrically conductive paste in which ceramic powder forming a ferroelectric ceramic layer for the multilayer ceramic capacitor is dispersed as a coexisting material, the coexisting material (barium titanate) in the external electrode between Ni particles as main components of the external electrode, thereby preventing the reaction between the Ni particles. Thus, densification of metal in the external electrode may be suppressed. As a result, gaps are more likely to occur in the external electrode, thereby leading to insulation deterioration caused by moisture infiltrating during plating and remaining in the gaps.
- Preferred embodiments of the present invention provide multilayer ceramic electronic components, in each of which formation of gaps is able to be reduced or prevented by densification of metal in an external electrode even when ceramic materials as coexisting materials are dispersed in the external electrode.
- a multilayer ceramic electronic component includes a multilayer body including a plurality of ceramic layers that are stacked, the multilayer body including a first main surface and a second main surface that face each other in a height direction, a first side surface and a second side surface that face each other in a width direction orthogonal or substantially orthogonal to the height direction, and a first end surface and a second end surface that face each other in a length direction orthogonal or substantially orthogonal to the height direction and the width direction; a first internal electrode layer that is disposed on each of the ceramic layers and exposed on the first end surface; a second internal electrode layer that is disposed on each of the ceramic layers and exposed on at least one surface of the second end surface, the first side surface, and the second side surface; a first external electrode that is connected to the first internal electrode layer and disposed on the first end surface; and a second external electrode that is connected to the second internal electrode layer and disposed on the at least one surface on which the second internal electrode layer is exposed.
- the first external electrode includes a first underlying electrode layer and a plurality of first plating layers located on the first underlying electrode layer.
- the second external electrode includes a second underlying electrode layer and a plurality of second plating layers located on the second underlying electrode layer.
- the first underlying electrode layer and the second underlying electrode layer each contain Ni as a first metal component, Sn as a second metal component, and a ceramic material, and each include an alloy portion that is provided around the ceramic material and includes an alloyed Ni defining the first metal component and an alloyed Sn defining the second metal component.
- multilayer ceramic electronic components are able to be provided, in each of which formation of gaps is able to be reduced or prevented by densification of metal in an external electrode even when ceramic materials as coexisting materials are dispersed in the external electrode.
- FIG. 1 is an external perspective view showing an example of a multilayer ceramic capacitor according to a first preferred embodiment of the present invention.
- FIG. 2 is a cross-sectional view taken along a line II-II in FIG. 1 .
- FIG. 3 is a schematic cross-sectional view of external electrodes located on both end surfaces in FIG. 2 and regions therearound in an enlarged manner.
- FIG. 4 is a cross-sectional view taken along a line IV-IV in FIG. 1 .
- FIG. 5 is a cross-sectional view taken along a line V-V in FIG. 2 .
- FIG. 6 is a cross-sectional view taken along a line VI-VI in FIG. 2 .
- FIG. 7 A is a cross-sectional view, which is taken along line II-II in FIG. 1 , showing a structure in which a facing electrode portion of an internal electrode layer of a multilayer ceramic capacitor according to a preferred embodiment of the present invention is divided into two sections.
- FIG. 7 B is a cross-sectional view, which is taken along line II-II in FIG. 1 , showing a structure in which a facing electrode portion of an internal electrode layer of a multilayer ceramic capacitor according to a preferred embodiment of the present invention is divided into three sections.
- FIG. 7 C is a cross-sectional view, which is taken along line II-II in FIG. 1 , showing a structure in which a facing electrode portion of an internal electrode layer of a multilayer ceramic capacitor according to a preferred embodiment of the present invention is divided into four sections.
- FIG. 8 is an external perspective view showing an example of a multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to a second preferred embodiment of the present invention.
- FIG. 9 is a top view showing an example of the multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to the second preferred embodiment of the present invention.
- FIG. 10 is a side view showing an example of the multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to the second preferred embodiment of the present invention.
- FIG. 11 is a cross-sectional view taken along a line XI-XI in FIG. 8 .
- FIG. 12 is a schematic cross-sectional view of external electrodes located on both end surfaces in FIG. 11 and regions therearound in an enlarged manner.
- FIG. 13 is a cross-sectional view taken along a line XIII-XIII in FIG. 8 .
- FIG. 14 is a schematic cross-sectional view of external electrodes located on both side surfaces in FIG. 13 and regions therearound in an enlarged manner.
- FIG. 15 is a cross-sectional view taken along a line XV-XV in FIG. 11 .
- FIG. 16 is a cross-sectional view taken along a line XVI-XVI in FIG. 11 .
- FIG. 17 shows a modification of a first internal electrode layer shown in FIG. 15 .
- FIG. 1 is an external perspective view showing an example of a multilayer ceramic capacitor according to the first preferred embodiment of the present invention.
- FIG. 2 is a cross-sectional view taken along a line II-II in FIG. 1 .
- FIG. 3 is a schematic cross-sectional view of external electrodes located on both end surfaces in FIG. 2 and regions therearound in an enlarged manner.
- FIG. 4 is a cross-sectional view taken along a line IV-IV in FIG. 1 .
- FIG. 5 is a cross-sectional view taken along a line V-V in FIG. 2 .
- FIG. 6 is a cross-sectional view taken along a line VI-VI in FIG. 2 .
- a multilayer ceramic capacitor 10 includes a multilayer body 12 having a rectangular or substantially rectangular parallelepiped shape.
- Multilayer body 12 includes a plurality of stacked ceramic layers 14 and a plurality of internal electrode layers 16 .
- Multilayer body 12 also includes a first main surface 12 a and a second main surface 12 b that face each other in a height direction x, a first side surface 12 c and a second side surface 12 d that face each other in a width direction y orthogonal or substantially orthogonal to height direction x, and a first end surface 12 e and a second end surface 12 f that face each other in a length direction z orthogonal or substantially orthogonal to height direction x and width direction y.
- Multilayer body 12 includes corner portions and ridge portions, each of which is preferably rounded.
- first main surface 12 a , second main surface 12 b , first side surface 12 c , second side surface 12 d , first end surface 12 e , and second end surface 12 f each may be partially or entirely provided with, for example, projections and recesses, and the like.
- the number of ceramic layers 14 including outer layers is preferably 15 or more and 700 or less, for example.
- multilayer body 12 In the stacking direction extending along a line connecting first main surface 12 a and second main surface 12 b , multilayer body 12 includes an effective layer portion 15 a in which internal electrode layers 16 face each other, a first outer layer portion 15 b located between first main surface 12 a and one of internal electrode layers 16 that is closest to first main surface 12 a , and a second outer layer portion 15 c located between second main surface 12 b and one of internal electrode layers 16 that is closest to second main surface 12 b.
- First outer layer portion 15 b includes a plurality of ceramic layers 14 that are located on the first main surface 12 a side of multilayer body 12 and also located between first main surface 12 a and one of internal electrode layers 16 that is closest to first main surface 12 a.
- a region sandwiched between first outer layer portion 15 b and second outer layer portion 15 c is effective layer portion 15 a.
- the dimensions of multilayer body 12 are not particularly limited, it is preferable that, for example, the dimension of multilayer body 12 in length direction z is about 0.2 mm or more and about 10.0 mm or less, the dimension of multilayer body 12 in width direction y is about 0.1 mm or more and about 10.0 mm or less, and the dimension of multilayer body 12 in height direction x is about 0.1 mm or more and about 5.0 mm or less.
- Ceramic layer 14 can be made of a dielectric material such as a ceramic material, for example.
- a dielectric material can be made of dielectric ceramic containing components such as BaTiO 3 , CaTiO 3 , SrTiO 3 , or CaZrO 3 , for example.
- a material additionally containing a sub-component such as an Mn compound, an Fe compound, a Cr compound, a Co compound, or an Ni compound, for example
- a sub-component such as an Mn compound, an Fe compound, a Cr compound, a Co compound, or an Ni compound, for example
- the multilayer ceramic electronic component defines and functions as a ceramic piezoelectric element.
- the piezoelectric ceramic material may be a lead zirconate titanate (PZT)-based ceramic material or the like.
- the multilayer ceramic electronic component defines and functions as a thermistor element.
- the semiconductor ceramic material may be a spinel-based ceramic material or the like, for example.
- the multilayer ceramic electronic component defines and functions as an inductor element.
- internal electrode layer 16 is a coil-shaped conductor.
- a specific example of the magnetic ceramic material may be a ferrite ceramic material or the like, for example.
- the thickness of fired ceramic layer 14 is preferably about 0.4 ⁇ m or more and about 10.0 ⁇ m or less, for example.
- multilayer body 12 includes, as a plurality of internal electrode layers 16 , a plurality of first internal electrode layers 16 a and a plurality of second internal electrode layers 16 b , each of which has a rectangular or approximately rectangular shape, for example.
- the plurality of first internal electrode layers 16 a and the plurality of second internal electrode layers 16 b are buried so as to be alternately arranged at regular intervals in the stacking direction of multilayer body 12 .
- First internal electrode layers 16 a and second internal electrode layers 16 b may be disposed in parallel or substantially in parallel with a mounting surface or may be disposed to be vertical to the mounting surface.
- Each first internal electrode layer 16 a includes a first facing electrode portion 18 a that faces second internal electrode layer 16 b , and a first extending electrode portion 20 a located on one end side of first internal electrode layer 16 a and extending from first facing electrode portion 18 a to first end surface 12 e of multilayer body 12 .
- First extending electrode portion 20 a includes an end portion extending to first end surface 12 e and exposed from first end surface 12 e.
- Each second internal electrode layer 16 b includes a second facing electrode portion 18 b that faces first internal electrode layer 16 a , and a second extending electrode portion 20 b located on one end side of second internal electrode layer 16 b and extending from second facing electrode portion 18 b to second end surface 12 f of multilayer body 12 .
- Second extending electrode portion 20 b includes an end portion extending to second end surface 12 f and exposed from second end surface 12 f.
- first facing electrode portion 18 a of first internal electrode layer 16 a and second facing electrode portion 18 b of second internal electrode layer 16 b each have a rectangular or substantially rectangular shape, but is not particularly limited. Also, each of corner portions of the rectangular or substantially rectangular shape may be rounded or may have an inclined shape (in a tapered shape, for example).
- first extending electrode portion 20 a of first internal electrode layer 16 a and second extending electrode portion 20 b of second internal electrode layer 16 b each have a rectangular or substantially rectangular shape, but is not particularly limited. Also, each of corner portions of the rectangular or substantially rectangular shape may be rounded or may have in an inclined shape (in a tapered shape, for example).
- Multilayer body 12 includes a side portion (W gap) 24 a provided between first side surface 12 c and one end of each of first facing electrode portion 18 a and second facing electrode portion 18 b in width direction y, and between second side surface 12 d and the other end of each of first facing electrode portion 18 a and second facing electrode portion 18 b in width direction y. Furthermore, multilayer body 12 includes an end portion (L gap) 24 b provided between second end surface 12 f and one end of first internal electrode layer 16 a that is opposite to first extending electrode portion 20 a , and between first end surface 12 e and one end of second internal electrode layer 16 b that is opposite to second extending electrode portion 20 b.
- W gap side portion
- L gap end portion
- Internal electrode layer 16 contains electrically conductive materials made of, for example, metals such as Ni, Cu, Ag, Pd, or Au, or an alloy such as an Ag—Pd alloy containing at least one of these metals. Internal electrode layer 16 may further contain dielectric particles of the same composition base as that of ceramic contained in ceramic layer 14 .
- Internal electrode layer 16 is preferably made of a material containing Ni as the third metal component and Sn as the fourth metal component. Also, Ni as the third metal component and Sn as the third metal component may also be partially alloyed. Thus, alloying of Ni and Sn changes the state (an electrical barrier height) at and around the interface of internal electrode layer 16 with ceramic layer 14 , thus contributing to an improvement in high-temperature load life. This results in multilayer ceramic capacitor 10 that has excellent reliability (improved in high-temperature load life) during voltage application.
- the fourth metal component may be an Sn material made of, for example, any one of metal containing Sn and an Sn compound, or, in place of Sn, may be tin oxide powder represented by Sno or SnO 2 .
- Ni as the third metal component is a main component while Sn as the fourth metal component is a sub-component.
- the content of Sn is preferably about 0.001 mol or more and about 0.1 mol or less, for example.
- the content of Sn is about 0.001 mol or more, the effect of containing Sn is more effectively achieved.
- the melting point of internal electrode layer 16 falls within a preferable range, so that problems, such as balling, are less likely to occur.
- the above-described state can be achieved by, adding, to an electrically conductive paste for internal electrode formation, Sn of the fourth metal component as a sub-component for Ni of the third metal component as a main component; or adding an Ni—Sn alloy to the electrically conductive paste for internal electrode formation.
- the portion provided by alloying Ni as the third metal component and Sn as the fourth metal component includes an alloy layer 22 provided at an interface between ceramic layer 14 and internal electrode layer 16 so as to cover internal electrode layer 16 .
- Alloy layer 22 includes a first alloy layer 22 a and a second alloy layer 22 b .
- First alloy layer 22 a covers first internal electrode layer 16 a
- second alloy layer 22 b covers second internal electrode layer 16 b .
- alloy layer 22 provided by alloying Ni and Sn is thus included to change the state (an electrical height) at and around the interface of internal electrode layer 16 with ceramic layer 14 , and thus contribute to improvement in high-temperature load life.
- multilayer ceramic capacitor 10 having excellent reliability (improved in high-temperature load life) during voltage application is obtained.
- the cross section of multilayer body 12 is polished (for example, to expose an LT cross section at 1 ⁇ 2 W position) and thereafter checked by WDX analysis for composition differences. Then, based on the composition differences, the range of alloy layer 22 can be specified. Furthermore, a portion of the cross section (including ceramic layer 14 and internal electrode layer 16 ) is sliced and then subjected to TEM analysis. Thus, the composition differences can be more specifically checked.
- the thickness of internal electrode layer 16 is preferably about 0.2 ⁇ m or more and about 2.0 ⁇ m or less, for example. Also, the number of internal electrode layers 16 is preferably 15 or more and 200 or less, for example.
- External electrode 26 is disposed on the first end surface 12 e side and the second end surface 12 f side of multilayer body 12 .
- External electrode 26 includes a first external electrode 26 a and a second external electrode 26 b.
- First external electrode 26 a is disposed on first end surface 12 e of multilayer body 12 and extends from first end surface 12 e to partially cover each of first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d .
- first external electrode 26 a is electrically connected to first extending electrode portion 20 a of first internal electrode layer 16 a .
- First external electrode 26 a may be provided only on first end surface 12 e of multilayer body 12 .
- Second external electrode 26 b is disposed on second end surface 12 f of multilayer body 12 , and extends from second end surface 12 f to partially cover each of first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d .
- second external electrode 26 b is electrically connected to second extending electrode portion 20 b of second internal electrode layer 16 b .
- Second external electrode 26 b may be provided only on second end surface 12 f of multilayer body 12 .
- first facing electrode portion 18 a of first internal electrode layer 16 a and second facing electrode portion 18 b of second internal electrode layer 16 b face each other with ceramic layer 14 interposed therebetween, thus generating a capacitance.
- a capacitance can be obtained between first external electrode 26 a to which first internal electrode layer 16 a is connected and second external electrode 26 b to which second internal electrode layer 16 b is connected, thus having a characteristic of a capacitor.
- floating internal electrode layers 16 c not extending to either of first end surface 12 e and second end surface 12 f may be provided in addition to first internal electrode layer 16 a and second internal electrode layer 16 b , as shown in FIGS. 7 A to 7 C , thus providing a structure in which facing electrode portion 18 c is divided into a plurality of sections by floating internal electrode layers 16 c .
- Examples of the structure include a 2-stage structure as shown in FIG. 7 A , a 3-stage structure as shown in FIG. 7 B , a 4-stage structure as shown in FIG. 7 C , and 5-or-more-stage structure.
- the structure including facing electrode portion 18 c divided into a plurality of sections in this way enables to a configuration in which a plurality of capacitor components are provided between internal electrode layers 16 a , 16 b , and 16 c facing each other and these capacitor components are connected in series.
- a relatively low voltage is applied to each capacitor component, so that the multilayer ceramic capacitor can have an increased breakdown voltage.
- External electrode 26 includes an underlying electrode layer 28 disposed on the surface of multilayer body 12 , and a plating layer 30 covering underlying electrode layer 28 .
- Underlying electrode layer 28 includes a first underlying electrode layer 28 a and a second underlying electrode layer 28 b.
- First underlying electrode layer 28 a is disposed on first end surface 12 e of multilayer body 12 , and extends from first end surface 12 e to partially cover each of first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d.
- Second underlying electrode layer 28 b is disposed on second end surface 12 f of multilayer body 12 , and extends from second end surface 12 f to partially cover each of first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d.
- First underlying electrode layer 28 a may be disposed only on first end surface 12 e of multilayer body 12
- second underlying electrode layer 28 b may be disposed only on second end surface 12 f of multilayer body 12 .
- first underlying electrode layer 28 a located on first end surface 12 e and second underlying electrode layer 28 b located on second end surface 12 f each are, for example, about 3 ⁇ m or more and about 160 ⁇ m or less in thickness in a center portion in the stacking direction.
- a thickness is preferably, for example, about 3 ⁇ m or more and about 40 ⁇ m or less in the center portion in length direction z in each of first underlying electrode layer 28 a and second underlying electrode layer 28 b that are located on each of first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d.
- Underlying electrode layer 28 (first underlying electrode layer 28 a and second underlying electrode layer 28 b ) contains Ni as the first metal component, Sn as the second metal component, and ceramic particles (a ceramic material). Underlying electrode layer 28 also includes a portion provided by alloying Ni as the first metal component and Sn as the second metal component. Thus, Ni as the first metal component and Sn as the second metal component in underlying electrode layer 28 are partially alloyed to lower the melting point. Accordingly, the sinterability of underlying electrode layer 28 can be improved, and the reaction of the alloy in underlying electrode layer 28 is activated. Thus, densification of underlying electrode layer 28 progresses. As a result, formation of gaps that may occur inside underlying electrode layer 28 can be reduced or prevented.
- multilayer ceramic capacitor 10 enables reduction or prevention of formation of gaps through which moisture infiltrates during formation of a plating layer and the like.
- moisture does not infiltrate into each external electrode, and also, moisture can be prevented from infiltrating into multilayer body 12 , with the result that insulation deterioration can be prevented.
- Ni as the first metal component is a main component
- Sn as the second metal component is a sub-component
- ceramic particles (ceramic material) 38 randomly exist in first underlying electrode layer 28 a and second underlying electrode layer 28 b , each of which is made of Ni. Also, an alloy portion 40 is provided that is formed by alloying Ni as the first metal component and Sn as the second metal component so as to surround each of ceramic particles 38 .
- Alloy portion 40 in underlying electrode layer 28 is checked by the following method. Specifically, plating layer 30 of multilayer ceramic capacitor 10 is first peeled off to expose underlying electrode layer 28 . Then, XRD analysis is conducted on the end surface of the exposed underlying electrode layer 28 to extract only peaks of Ni. Thus, it can be checked that the peak position of Ni in the portion containing Sn is shifted to the low angle side with respect to the portion not containing Sn, and thus, it can be determined that Ni is partially alloyed.
- the alloy portion 40 may exist entirely around ceramic particle 38 or may exist on only a portion of ceramic particle 38 .
- ceramic particles 38 may be partially in contact with each other with alloy portion 40 interposed therebetween, or may be space apart and contacting each other.
- an end surface alloy layer 42 is provided that is formed by alloying Ni as the first metal component and Sn as the second metal component contained in underlying electrode layer 28 , or by alloying Ni as the third metal component contained in internal electrode layer 16 and Sn as the second metal component contained in underlying electrode layer 28 .
- End surface alloy layer 42 includes a first end surface alloy layer 42 a and a second end surface alloy layer 42 b .
- First end surface alloy layer 42 a is disposed at the interface between first end surface 12 e of multilayer body 12 and first underlying electrode layer 28 a .
- Second end surface alloy layer 42 b is disposed at the interface between second end surface 12 f of multilayer body 12 and second underlying electrode layer 28 b.
- Ni as the third metal component of internal electrode layer 16 may be alloyed with Sn as the fourth metal component.
- end surface alloy layer 42 may be provided that is made of the first metal component to the fourth metal component contained in each of internal electrode layer 16 and underlying electrode layer 28 .
- First end surface alloy layer 42 a disposed at the interface between first underlying electrode layer 28 a and multilayer body 12 may be disposed at the entire interface between first underlying electrode layer 28 a and multilayer body 12 , or may be disposed at a portion of the interface between first underlying electrode layer 28 a and multilayer body 12 .
- second end surface alloy layer 42 b disposed at the interface between second underlying electrode layer 28 b and multilayer body 12 may be disposed at the entire interface between second underlying electrode layer 28 b and multilayer body 12 , or may be disposed at a portion of the interface between second underlying electrode layer 28 b and multilayer body 12 .
- end surface alloy layer 42 is disposed at the interface between underlying electrode layer 28 and multilayer body 12 in this way, the melting point at and around each of both end surfaces of multilayer body 12 can be lowered. Consequently, the sinterability of ceramic layer 14 located near each the end surfaces of the multilayer body 12 can be more effectively improved.
- the amounts of Ni as the first metal component, Sn as the second metal component, and ceramic particles (a ceramic material) contained in underlying electrode layer 28 for example, assuming that the sum of Ni as the first metal component and Sn as the second metal component is 100 mol, the content of Sn is preferably about 0.001 mol or more and about 0.1 mol or less, and the content of the ceramic particles (a ceramic material) is preferably about 5% or more and about 50% or less with respect to the entire volume of underlying electrode layer 28 .
- the dielectric material as a ceramic material contained in underlying electrode layer 28 includes at least one selected from BaTiO 3 , CaTiO 3 , SrTiO 3 , or CaZrO 3 , for example. Since the dielectric material is contained as a coexisting material in underlying electrode layer 28 , the dielectric material contained in underlying electrode layer 28 reacts with ceramic layer 14 in each of first outer layer portion 15 b and second outer layer portion 15 c of multilayer body 12 , to thus achieve an anchor effect. Consequently, the adhesive force between underlying electrode layer 28 and multilayer body 12 is improved.
- examples of the piezoelectric ceramic material as a ceramic material contained in underlying electrode layer 28 may be a PZT (lead zirconate titanate)-based ceramic material and the like.
- examples of the semiconductor ceramic material as a ceramic material contained in underlying electrode layer 28 may be a spinel-based ceramic material, and the like.
- examples of the magnetic ceramic material as a ceramic material contained in underlying electrode layer 28 may be a ferrite ceramic material and the like.
- Plating layer 30 includes a first plating layer 30 a and a second plating layer 30 b.
- First plating layer 30 a is disposed to cover first underlying electrode layer 28 a.
- Second plating layer 30 b is disposed to cover second underlying electrode layer 28 b.
- Plating layer 30 preferably contains at least one selected, for example, from Cu, Ni, Sn, Ag, Pd, an Ag—Pd alloy, Au, and the like.
- Plating layer 30 may include a plurality of layers.
- plating layer 30 includes a lower plating layer 32 covering underlying electrode layer 28 , an intermediate plating layer 34 covering lower plating layer 32 ; and an upper plating layer 36 covering intermediate plating layer 34 .
- the thickness of one plating layer is preferably about 1 ⁇ m or more and about 15 ⁇ m or less, for example.
- Lower plating layer 32 includes a first lower plating layer 32 a and a second lower plating layer 32 b.
- First lower plating layer 32 a covers first underlying electrode layer 28 a . Specifically, it is preferable that first lower plating layer 32 a is disposed on the surface of first underlying electrode layer 28 a that is located on first end surface 12 e , so as to also extend to the surface of first underlying electrode layer 28 a that is located on first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d . First lower plating layer 32 a may be disposed only on the surface of first underlying electrode layer 28 a disposed on first end surface 12 e.
- Second lower plating layer 32 b to covers second underlying electrode layer 28 b .
- second lower plating layer 32 b is disposed on the surface of second underlying electrode layer 28 b that is located on second end surface 12 f , so as to also extend to the surface of second underlying electrode layer 28 b that is located on first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d .
- Second lower plating layer 32 b may be disposed only on the surface of second underlying electrode layer 28 b disposed on second end surface 12 f.
- lower plating layer 32 is preferably defined by a Cu plating layer, for example.
- Lower plating layer 32 is defined by a Cu plating layer and covers the surface of underlying electrode layer 28 , thus achieving an effect of reducing or preventing infiltration of a plating solution.
- the stress of the Cu plating layer applied to the multilayer body is preferably about ⁇ 400 MPa or more and about ⁇ 3 MPa or less, for example.
- the compressive stress of the Cu plating layer may reduce the tensile stress to be applied to the end portion of underlying electrode layer 28 after multilayer ceramic capacitor 10 is mounted on a mounting substrate, with the result that the effect of improving the mechanical strength is achieved.
- Intermediate plating layer 34 includes a first intermediate plating layer 34 a and a second intermediate plating layer 34 b.
- First intermediate plating layer 34 a covers first lower plating layer 32 a .
- first intermediate plating layer 34 a is disposed on the surface of first lower plating layer 32 a that is located on first end surface 12 e so as to also extend to the surface of first lower plating layer 32 a that is located on first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d .
- First intermediate plating layer 34 a may be disposed only on the surface of first lower plating layer 32 a disposed on first end surface 12 e.
- Second intermediate plating layer 34 b covers second lower plating layer 32 b .
- second intermediate plating layer 34 b is disposed on the surface of second lower plating layer 32 b that is located on second end surface 12 f so as to also extend to the surface of second lower plating layer 32 b that is located on first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d .
- second intermediate plating layer 34 b may be disposed only on the surface of second lower plating layer 32 b disposed on second end surface 12 f.
- intermediate plating layer 34 is preferably defined by an Ni plating layer, for example. Intermediate plating layer 34 is defined an Ni plating layer and covers the surface of lower plating layer 32 . As a result, underlying electrode layer 28 can be prevented from being eroded by solder used when multilayer ceramic capacitor 10 is mounted on a mounting substrate.
- Upper plating layer 36 includes a first upper plating layer 36 a and a second upper plating layer 36 b.
- First upper plating layer 36 a covers first intermediate plating layer 34 a .
- first upper plating layer 36 a is disposed on the surface of first intermediate plating layer 34 a that is located on first end surface 12 e , so as to also extend to the surface of first intermediate plating layer 34 a that is located on first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d .
- First upper plating layer 36 a may be disposed only on the surface of first intermediate plating layer 34 a disposed on first end surface 12 e.
- Second upper plating layer 36 b covers second intermediate plating layer 34 b .
- second upper plating layer 36 b is disposed on the surface of second intermediate plating layer 34 b that is located on second end surface 12 f , so as to also extend to the surface of second intermediate plating layer 34 b that is located on first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d .
- Second upper plating layer 36 b may be disposed only on the surface of second intermediate plating layer 34 b disposed on second end surface 12 f.
- upper plating layer 36 is preferably defined by an Sn plating layer, for example.
- Upper plating layer 36 is defined by an Sn plating layer and covers the surface of intermediate plating layer 34 , to thus improve the wettability of solder used when multilayer ceramic capacitor 10 is mounted on a mounting substrate, with the result that multilayer ceramic capacitor 10 can be readily mounted.
- plating layer 30 includes three layers including lower plating layer 32 , intermediate plating layer 34 , and upper plating layer 36 , but the present invention is not limited thereto, and may include only lower plating layer 32 , may include only of intermediate plating layer 34 , or may include only of upper plating layer 36 .
- multilayer ceramic capacitor 10 including multilayer body 12 , first external electrode 26 a , and second external electrode 26 b has a dimension in length direction Z defined as an L dimension, a dimension in height direction X defined as a T dimension, and a dimension in width direction y defined as a W dimension.
- the L dimension in length direction z is about 0.20 mm or more and about 10.0 mm or less
- the W dimension in width direction y is about 0.10 mm or more and about 10.0 mm or less
- the T dimension in height direction x is about 0.10 mm or more and about 5.0 mm or less, for example.
- underlying electrode layer 28 contains Ni as the first metal component, Sn as the second metal component, and ceramic particles (a ceramic material).
- Ni as the first metal component and Sn as the second metal component in underlying electrode layer 28 are partially alloyed to lower the melting point. Accordingly, the sinterability of underlying electrode layer 28 can be improved to thus activate the reaction of the alloy in underlying electrode layer 28 , and thus, densification of external electrode 26 progresses. As a result, formation of gaps that may occur in underlying electrode layer 28 can be reduced or prevented.
- multilayer ceramic capacitor 10 shown in FIG. 1 enables reduction or prevention of occurrence of gaps through which moisture infiltrates during formation of a plating layer or the like. Accordingly, moisture does not infiltrate into each external electrode, and thus, moisture can be prevented from infiltrating also into multilayer body 12 , so that insulation deterioration can be prevented. As a result, multilayer ceramic capacitor 10 can be improved in reliability.
- multilayer ceramic capacitor will be described as an example of a multilayer ceramic electronic component according to a second preferred embodiment of the present invention.
- the multilayer ceramic capacitor according to the present second preferred embodiment is a three-terminal multilayer ceramic capacitor.
- FIG. 8 is an external perspective view showing an example of a multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to the second preferred embodiment of the present invention.
- FIG. 9 is a top view showing an example of the multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to the second preferred embodiment of the present invention.
- FIG. 10 is a side view showing an example of the multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to the second preferred embodiment of the present invention.
- FIG. 11 is a cross-sectional view taken along a line XI-XI in FIG.
- FIG. 12 is a schematic cross-sectional view of external electrodes located on both end surfaces in FIG. 11 and regions therearound in an enlarged manner.
- FIG. 13 is a cross-sectional view taken along a line XIII-XIII in FIG. 8 .
- FIG. 14 is a schematic cross-sectional view of external electrodes located on both side surfaces in FIG. 13 and regions therearound in an enlarged manner.
- FIG. 15 is a cross-sectional view taken along a line XV-XV in FIG. 11 .
- FIG. 16 is a cross-sectional view taken along a line XVI-XVI in FIG. 11 .
- a multilayer ceramic capacitor 110 includes a multilayer body 12 having a rectangular or substantially rectangular parallelepiped shape, for example.
- Multilayer body 12 includes a plurality of stacked ceramic layers 14 and a plurality of internal electrode layers 116 .
- Multilayer body 12 also includes a first main surface 12 a and a second main surface 12 b that face each other in a height direction x, a first side surface 12 c and a second side surface 12 d that face each other in a width direction y orthogonal or substantially orthogonal to height direction x, and a first end surface 12 e and a second end surface 12 f that face each other in a length direction z orthogonal or substantially orthogonal to height direction x and width direction y.
- This multilayer body 12 includes corner portions and ridge portions, each of which is preferably rounded.
- first main surface 12 a , second main surface 12 b , first side surface 12 c , second side surface 12 d , first end surface 12 e , and second end surface 12 f each may be partially or entirely provided with, for example, projections and recesses, and the like.
- the dimension of multilayer body 12 in length direction z is not necessarily longer than the dimension of multilayer body 12 in width direction y.
- multilayer body 12 In the stacking direction extending along a line connecting first main surface 12 a and second main surface 12 b , multilayer body 12 includes an effective layer portion 15 a in which internal electrode layers 116 face each other, a first outer layer portion 15 b located between first main surface 12 a and one of internal electrode layers 116 that is closest to first main surface 12 a , and a second outer layer portion 15 c located between second main surface 12 b and one of internal electrode layers 116 that is closest to second main surface 12 b.
- First outer layer portion 15 b includes a plurality of ceramic layers 14 that are located on the first main surface 12 a side of multilayer body 12 and also located between first main surface 12 a and one of internal electrode layers 116 that is closest to first main surface 12 a.
- Second outer layer portion 15 c includes a plurality of ceramic layers 14 that are located on the second main surface 12 b side of multilayer body 12 and also located between second main surface 12 b and one of internal electrode layers 116 that is closest to second main surface 12 b.
- a region sandwiched between first outer layer portion 15 b and second outer layer portion 15 c is effective layer portion 15 a.
- ceramic layer 14 is made of the same or substantially the same material as that of multilayer ceramic capacitor 10 , the description thereof will not be repeated.
- the average thickness of the fired ceramic layers 14 in the stacking direction is the same or substantially the same as that of multilayer ceramic capacitor 10 , the description thereof will not be repeated.
- Multilayer body 12 includes, as a plurality of internal electrode layers 116 , a plurality of first internal electrode layers 116 a and a plurality of second internal electrode layers 116 b .
- the plurality of first internal electrode layers 116 a and the plurality of second internal electrode layers 116 b are buried so as to be alternately arranged at regular intervals in the stacking direction of multilayer body 12 .
- first internal electrode layer 116 a includes a first facing electrode portion 118 a that faces second internal electrode layer 116 b , one first extending electrode portion 120 al extending from first facing electrode portion 118 a to first end surface 12 e of multilayer body 12 , and the other second extending electrode portion 120 a 2 extending from first facing electrode portion 118 a to second end surface 12 f of multilayer body 12 .
- one first extending electrode portion 120 al is exposed on first end surface 12 e of multilayer body 12 while the other first extending electrode portion 120 a 2 is exposed on second end surface 12 f of multilayer body 12 .
- first internal electrode layer 116 a is not exposed on first side surface 12 c and second side surface 12 d of multilayer body 12 .
- second internal electrode layer 116 b has an approximately cross shape, and includes a second facing electrode portion 118 b that faces first internal electrode layer 116 a , one second extending electrode portion 120 b 1 extending from second facing electrode portion 118 b to first side surface 12 c of multilayer body 12 , and the other second extending electrode portion 120 b 2 extending from second facing electrode portion 118 b to second side surface 12 d of multilayer body 12 .
- one second extending electrode portion 120 b 1 is exposed on first side surface 12 c of multilayer body 12 while the other second extending electrode portion 120 b 2 is exposed on second side surface 12 d of multilayer body 12 .
- second internal electrode layer 116 b is not exposed on first end surface 12 e and second end surface 12 f of multilayer body 12 .
- second facing electrode portion 118 b in second internal electrode layer 116 b are not chamfered, but may be chamfered. This can prevent overlapping between the four corner portions of second facing electrode portion 118 b and the corner portions of first facing electrode portion 118 a in first internal electrode layer 116 a , and thus, any electric field concentration can be reduced or prevented. As a result, any electric breakdown in the ceramic capacitor that may be caused by electric field concentration can be reduced or prevented.
- multilayer body 12 includes a side portion (hereinafter also referred to as a “W gap”) 24 a provided between first side surface 12 c and one end of first facing electrode portion 118 a of first internal electrode layer 116 a in width direction y, and between second side surface 12 d and the other end of first facing electrode portion 118 a of first internal electrode layer 116 a in width direction y, and also includes side portion 24 a provided between first side surface 12 c and one end of second facing electrode portion 118 b of second internal electrode layer 116 b in width direction y, and between second side surface 12 d and the other end of first facing electrode portion 118 a of second internal electrode layer 116 b in width direction y.
- W gap side portion
- multilayer body 12 includes an end portion (hereinafter also referred to as an “L gap”) 24 b provided between first end surface 12 e and one end of second internal electrode layer 116 b in length direction z, and between second end surface 12 f and the other end of second internal electrode layer 116 b in length direction z.
- L gap an end portion
- internal electrode layer 116 contains Ni as the third metal component and Sn as the fourth metal component.
- Ni as the third metal component and Sn as the third metal component may be partially alloyed.
- alloying of Ni and Sn changes the state (an electrical barrier height) at and around the interface of internal electrode layer 116 with ceramic layer 14 , thus contributing to an improvement in high-temperature load life.
- multilayer ceramic capacitor 10 having excellent reliability (improved in high-temperature load life) during voltage application is obtained.
- Ni as the third metal component is a main component and Sn as the fourth metal component is a sub-component.
- the content of Sn is preferably about 0.001 mol or more and about 0.1 mol or less, for example.
- the above-described state can be achieved by adding, to a paste for an internal electrode, Sn of the fourth metal component as a sub-component for Ni of the third metal component as a main component, or by adding an Ni—Sn alloy to the paste for an internal electrode.
- a portion provided by alloying Ni as the third metal component and Sn as the fourth metal component includes an alloy layer 122 provided at an interface between ceramic layer 14 and internal electrode layer 116 so as to cover internal electrode layer 116 .
- Alloy layer 122 includes a first alloy layer 122 a and a second alloy layer 122 b .
- First alloy layer 122 a covers first internal electrode layer 116 a while second alloy layer 122 b covers second internal electrode layer 116 b.
- first internal electrode layer 116 a may be provided such that the width of one first extending electrode portion 120 al of first internal electrode layer 116 a , which extends to first end surface 12 e , tapers toward first end surface 12 e , and such that the width of the other first extending electrode portion 120 a 2 of first internal electrode layer 116 a , which extends to second end surface 12 f , tapers toward second end surface 12 f (a tapered shape).
- first facing electrode portion 118 a of first internal electrode layer 116 a and the plane of second facing electrode portion 118 b of second internal electrode layer 116 b which face each other, are preferably ensured to have at least the same or substantially the same area.
- an external electrode 26 is disposed on each of the first end surface 12 e side, the second end surface 12 f side, the first side surface 12 c side, and the second side surface 12 d side of multilayer body 12 .
- External electrode 26 includes a first external electrode 26 a , a second external electrode 26 b , a third external electrode 26 c , and a fourth external electrode 26 d.
- First external electrode 26 a is disposed on first end surface 12 e of multilayer body 12 .
- First external electrode 26 a extends from first end surface 12 e of multilayer body 12 so as to partially cover each of first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d .
- First external electrode 26 a is electrically connected to one first extending electrode portion 120 al of first internal electrode layer 116 that is exposed on first end surface 12 e of multilayer body 12 .
- Second external electrode 26 b is disposed on second end surface 12 f of multilayer body 12 .
- Second external electrode 26 b extends from second end surface 12 f of multilayer body 12 so as to partially cover each of first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d .
- Second external electrode 26 b is electrically connected to the other first extending electrode portion 120 a 2 of first internal electrode layer 116 that is exposed on second end surface 12 f of multilayer body 12 .
- Third external electrode 26 c is disposed on first side surface 12 c of multilayer body 12 .
- Third external electrode 26 c extends from first side surface 12 c so as to partially cover each of first main surface 12 a and second main surface 12 b .
- Third external electrode 26 c is electrically connected to one second extending electrode portion 120 b 1 of second internal electrode layer 116 b that is exposed on first side surface 12 c of multilayer body 12 .
- Fourth external electrode 26 d is disposed on second side surface 12 d of multilayer body 12 . Fourth external electrode 26 d extend from second side surface 12 d so as to partially cover each of first main surface 12 a and second main surface 12 b . Fourth external electrode 26 d is electrically connected to the other second extending electrode portion 120 b 2 of second internal electrode layer 116 b that is exposed on second side surface 12 d of multilayer body 12 .
- first facing electrode portion 118 a of first internal electrode layer 116 a and second facing electrode portion 118 b of second internal electrode layer 116 b face each other with a ceramic layer 14 interposed therebetween, thus generating a capacitance.
- a capacitance can be obtained between first external electrode 26 a and second external electrode 26 b to which first internal electrode layer 116 a is connected, and third external electrode 26 c and fourth external electrode 26 d to which second internal electrode layer 116 b is connected, thus obtaining a characteristic of a capacitor.
- External electrode 26 includes an underlying electrode layer 28 disposed on the surface of multilayer body 12 , and a plating layer 30 covering underlying electrode layer 28 .
- Underlying electrode layer 28 includes a first underlying electrode layer 28 a , a second underlying electrode layer 28 b , a third underlying electrode layer 28 c , and a fourth underlying electrode layer 28 d.
- First underlying electrode layer 28 a is disposed on first end surface 12 e of multilayer body 12 and extends from first end surface 12 e so as to partially cover each of first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d.
- Second underlying electrode layer 28 b is disposed on second end surface 12 f of multilayer body 12 and extends from second end surface 12 f so as to partially cover each of first main surface 12 a , second main surface 12 b , first side surface 12 c , and second side surface 12 d.
- First underlying electrode layer 28 a may be disposed only on first end surface 12 e of multilayer body 12
- second underlying electrode layer 28 b may be disposed only on second end surface 12 f of multilayer body 12 .
- Third underlying electrode layer 28 c is disposed on first side surface 12 c of multilayer body 12 and extends from first side surface 12 c so as to partially cover each of first main surface 12 a and second main surface 12 b.
- Fourth underlying electrode layer 28 d is disposed on second side surface 12 d of multilayer body 12 and extends from second side surface 12 d so as to partially cover each of first main surface 12 a and second main surface 12 b.
- Third underlying electrode layer 28 c may be disposed only on first side surface 12 c of multilayer body 12
- fourth underlying electrode layer 28 d may be disposed only on second side surface 12 d of multilayer body 12 .
- Underlying electrode 28 layer (first underlying electrode layer 28 a , second underlying electrode layer 28 b , third underlying electrode layer 28 c , and fourth underlying electrode layer 28 d ) contains Ni as the first metal component, Sn as the second metal component, and ceramic particles (a ceramic material). Underlying electrode layer 28 also includes a portion formed by alloying Ni as the first metal component and Sn as the second metal component. Thus, Ni as the first metal component and Sn as the second metal component in underlying electrode layer 28 are partially alloyed, to thus lower the melting point. Accordingly, the sinterability of underlying electrode layer 28 can be improved, the reaction of the alloy in underlying electrode layer 28 is activated, and thus, densification of underlying electrode layer 28 progresses.
- multilayer ceramic capacitor 10 enables reduction or prevention of formation of gaps through which moisture infiltrates during formation of a plating layer or the like.
- moisture does not infiltrate into each external electrode, and also, moisture can be prevented from infiltrating also into multilayer body 12 , with the result that insulation deterioration can be prevented.
- Ni as the first metal component is a main component while Sn as the second metal component is a sub-component.
- ceramic particles (a ceramic material) 38 randomly exist in first underlying electrode layer 28 a and second underlying electrode layer 28 b , each of which is made of Ni, and each include an alloy portion 40 formed by alloying Ni as the first metal component and Sn as the second metal component such that each alloy portion 40 surrounds corresponding ceramic particle 38 .
- ceramic particles 38 randomly exist in third underlying electrode layer 28 c and fourth underlying electrode layer 28 d , each of which is made of Ni, and each include alloy portion 40 formed by alloying Ni as the first metal component and Sn as the second metal component such that each alloy portion 40 surrounds corresponding ceramic particle 38 .
- the alloy portion 40 may exist entirely around ceramic particle 38 or may exist on only a portion of ceramic particle 38 .
- ceramic particles 38 may be partially in contact with each other with alloy portion 40 interposed therebetween, or may be spaced apart without contacting each other.
- an end surface alloy layer 42 and a side surface alloy layer 44 are provided, each of which is formed by alloying Ni as the first metal component and Sn as the second metal component contained in underlying electrode layer 28 , or by alloying Ni as the third metal component contained in internal electrode layer 16 and Sn as the second metal component contained in underlying electrode layer 28 .
- End surface alloy layer 42 includes a first end surface alloy layer 42 a and a second end surface alloy layer 42 b .
- First end surface alloy layer 42 a is disposed at the interface between first end surface 12 e of multilayer body 12 and first underlying electrode layer 28 a .
- Second end surface alloy layer 42 b is disposed at the interface between second end surface 12 f of multilayer body 12 and second underlying electrode layer 28 b.
- Side surface alloy layer 44 includes a first side surface alloy layer 44 a and a second side surface alloy layer 44 b .
- First side surface alloy layer 44 a is disposed at the interface between first side surface 12 c of multilayer body 12 and third underlying electrode layer 28 c .
- Second side surface alloy layer 44 b is disposed at the interface between second side surface 12 d of multilayer body 12 and fourth underlying electrode layer 28 d.
- Ni as the third metal component and Sn as the fourth metal component in internal electrode layer 116 may be alloyed.
- end surface alloy layer 42 and side surface alloy layer 44 may be provided, each of which includes the first metal component to the fourth metal component contained in each of internal electrode layer 116 and underlying electrode layer 28 .
- First end surface alloy layer 42 a disposed at the interface between first underlying electrode layer 28 a and multilayer body 12 may be disposed at the entire interface between first underlying electrode layer 28 a and multilayer body 12 , or may be disposed at a portion of the interface between first underlying electrode layer 28 a and multilayer body 12 .
- Second end surface alloy layer 42 b disposed at the interface between second underlying electrode layer 28 b and multilayer body 12 may be disposed at the entire interface between second underlying electrode layer 28 b and multilayer body 12 , or may be disposed at a portion of the interface between second underlying electrode layer 28 b and multilayer body 12 .
- first side surface alloy layer 44 a disposed at the interface between third underlying electrode layer 28 c and multilayer body 12 may be disposed at the entire interface between third underlying electrode layer 28 c and multilayer body 12 , or may be disposed at a portion of the interface between third underlying electrode layer 28 c and multilayer body 12 .
- Second side surface alloy layer 44 b disposed at the interface between fourth underlying electrode layer 28 d and multilayer body 12 may be disposed at the entire interface between fourth underlying electrode layer 28 d and multilayer body 12 , or may be disposed at a portion of the interface between fourth underlying electrode layer 28 d and multilayer body 12 .
- Plating layer 30 includes a first plating layer 30 a , a second plating layer 30 b , a third plating layer 30 c , and a fourth plating layer 30 d.
- First plating layer 30 a is disposed to cover first underlying electrode layer 28 a.
- Second plating layer 30 b is disposed to cover second underlying electrode layer 28 b.
- Third plating layer 30 c is disposed to cover third underlying electrode layer 28 c.
- Fourth plating layer 30 d is disposed to cover fourth underlying electrode layer 28 d.
- Plating layer 30 may include a plurality of layers.
- plating layer 30 includes a lower plating layer 32 covering underlying electrode layer 28 , an intermediate plating layer 34 disposed to cover lower plating layer 32 , and an upper plating layer 36 disposed to cover intermediate plating layer 34 .
- first plating layer 30 a includes a first lower plating layer 32 a covering first underlying electrode layer 28 a , a first intermediate plating layer 34 a covering first lower plating layer 32 a , and a first upper plating layer 36 a covering first intermediate plating layer 34 a.
- Second plating layer 30 b includes a second lower plating layer 32 b covering second underlying electrode layer 28 b , a second intermediate plating layer 34 b covering second lower plating layer 32 b , and a second upper plating layer 36 b covering second intermediate plating layer 34 b.
- Third plating layer 30 c includes a third lower plating layer 32 c covering third underlying electrode layer 28 c , a third intermediate plating layer 34 c covering third lower plating layer 32 c , and a third upper plating layer 36 c covering third intermediate plating layer 34 c.
- Fourth plating layer 30 d includes a fourth lower plating layer 32 d covering fourth underlying electrode layer 28 d , a fourth intermediate plating layer 34 d covering fourth lower plating layer 32 d , and a fourth upper plating layer 36 d covering fourth intermediate plating layer 34 d.
- plating layer 30 in multilayer ceramic capacitor 110 are the same or substantially the same as those of multilayer ceramic capacitor 10 , the description thereof will not be repeated.
- a non-limiting example of a method of manufacturing a multilayer ceramic capacitor as a multilayer ceramic electronic component will be described.
- the method of manufacturing a multilayer ceramic capacitor according to the first preferred embodiment will be described.
- a ceramic paste containing ceramic powder is applied in a sheet shape, for example, by screen printing or the like, and then dried to produce a ceramic green sheet.
- an electrically conductive paste for internal electrode formation is prepared and applied in a prescribed pattern on the ceramic green sheet, for example, by screen printing or gravure printing, thereby preparing a ceramic green sheet on which a conductive pattern for internal electrode formation is formed, and a ceramic green sheet on which no conductive pattern for internal electrode formation is formed.
- Sn as the fourth metal component of a sub-component for Ni as the third metal component of a main component is contained in the metal component of the internal electrode layer
- Sn as the fourth metal component of a sub-component for Ni as the third metal component of a main component of the electrically conductive paste for internal electrode formation is added to the electrically conductive paste for internal electrode formation, or an Ni—Sn alloy is added to the electrically conductive paste for internal electrode formation.
- the content of Sn is adjusted between about 0.001 mol or more and about 0.1 mol or less, for example, assuming that the sum of Ni as the third metal component and Sn as the fourth metal component is about 100 mol.
- a ceramic paste and an electrically conductive paste for internal electrode formation may contain a known organic binder or a known organic solvent, for example.
- ceramic green sheets for outer layers are prepared, on which no conductive pattern for internal electrode formation is formed. Then, a prescribed number of these ceramic green sheets for outer layers are stacked, on which ceramic green sheets on which conductive patterns for internal electrode formation are formed are sequentially stacked, and further, a prescribed number of ceramic green sheets on which no conductive pattern for internal electrode formation is formed are stacked, to thus produce a mother multilayer body. In this case, a plurality of ceramic green sheets on which conductive patterns for internal electrode formation are printed are stacked such that extending portions of the conductive patterns for internal electrode formation extend alternately toward the opposite sides, thus producing a multilayer sheet.
- this multilayer sheet is press-fitted in the stacking direction by, for example, hydrostatic pressing or the like to thus produce a multilayer block.
- the multilayer block is cut into a prescribed shape and dimension so as to cut out a raw multilayer body chip.
- barrel polishing or the like for example, may be provided to the raw multilayer body chip such that corner portions and ridge portions are rounded.
- both end surfaces of the raw multilayer body chip are applied with an electrically conductive paste for external electrode, which contains Ni as the first metal component, Sn as the second metal component, BaTiO 3 and the like as ceramic particles (a ceramic material), a solvent, a dispersing agent, and the like.
- the amounts of Ni as the first metal component, Sn as the second metal component, and BaTiO 3 and the like as ceramic particles (a ceramic material) that are contained in the electrically conductive paste for external electrode are adjusted such that the content of Sn is set at about 0.001 mol or more and about 0.1 mol or less, for example, assuming that the sum of Ni as the first metal component and Sn as the second metal component is 100 mol, and also such that the content of the ceramic material is set at about 5% or more and about 50% or less, for example, with respect to the entire volume of the underlying electrode layer.
- the raw multilayer body chip and the electrically conductive paste for external electrode applied to the raw multilayer body chip are simultaneously baked to thus form a multilayer body including a baked layer formed as an underlying electrode layer.
- the plating layer 30 is formed on the surface of the underlying electrode layer.
- the plating layer is formed to include a Cu plating layer as a lower plating layer, an Ni plating layer as an intermediate plating layer, and an Sn plating layer as an upper plating layer.
- multilayer ceramic capacitor 10 shown in FIG. 1 is manufactured.
- a multilayer ceramic capacitor according to Comparative Example 1 is the same or substantially the same as the multilayer ceramic capacitor in Example 1, except that the underlying electrode layer does not contain Sn.
- the specifications will be hereinafter described in detail.
- a multilayer ceramic capacitor according to Comparative Example 2 is the same or substantially the same as the multilayer ceramic capacitor in Example 2, except that the underlying electrode layer does not contain Sn.
- the specifications will be hereinafter described in detail.
- the underlying electrode layer of the external electrode contains Ni as the first metal component that is a main component and Sn as the second metal component that is a sub-component.
- the underlying electrode layer of the external electrode contained only Ni as the first metal component but did not contain Sn as the second metal component that is a sub-component. Consequently, densification of the fired external electrode did not progress, and thus, all ten samples were rated as defective in the result of the moisture resistance reliability test.
- the underlying electrode layer of the external electrode contains Ni as the first metal component that is a main component and Sn as the second metal component that is a sub-component.
- Ni and Sn are partially alloyed in the underlying electrode layer, and therefore, the melting point is lowered. Accordingly, the sinterability of the underlying electrode layer is improved to thus activate the reaction of the alloy in the underlying electrode layer, and thus, densification of the external electrode progresses, with the result that formation of gaps that may occur in the underlying electrode layer is reduced or prevented.
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Abstract
A multilayer ceramic electronic component includes a multilayer body and an external electrode on each of both end surfaces of the multilayer body. The external electrode includes an underlying electrode layer and a plating layer that is disposed on the underlying electrode layer. The underlying electrode layer includes Ni as a first metal component, Sn as a second metal component, and a ceramic material, and includes an alloy portion that is provided around the ceramic material and includes an alloyed Ni defining the first metal component and an alloyed Sn defining the second metal component.
Description
- This application claims the benefit of priority to Japanese Patent Application No. 2019-233671 filed on Dec. 25, 2019. The entire contents of this application are hereby incorporated herein by reference.
- The present invention relates to a multilayer ceramic electronic component.
- In recent years, multilayer ceramic electronic components represented by multilayer ceramic capacitors have been increasingly used in more severe environments than conventional environments.
- In order to deal with the moisture resistance load caused by infiltration of moisture from an external electrode portion under such a circumstance, a multilayer ceramic capacitor as described below has been proposed.
- Specifically, the proposed multilayer ceramic capacitor prevents formation of gaps between a ceramic body and an external electrode to thereby improve the adhesiveness between the external electrode and the ceramic body. As a multilayer ceramic capacitor having such a configuration, for example, Japanese Patent Laid-Open No. 05-003134 discloses a technique for using an electrically conductive paste for an external electrode connected to internal electrodes stacked inside a multilayer ceramic capacitor. In this electrically conductive paste, ceramic powder forming a ferroelectric ceramic layer for the multilayer ceramic capacitor is dispersed as a coexisting material.
- The multilayer ceramic capacitor disclosed in Japanese Patent Laid-Open No. 05-003134, however, causes the following problems. Specifically, when an external electrode contains an electrically conductive paste in which ceramic powder forming a ferroelectric ceramic layer for the multilayer ceramic capacitor is dispersed as a coexisting material, the coexisting material (barium titanate) in the external electrode between Ni particles as main components of the external electrode, thereby preventing the reaction between the Ni particles. Thus, densification of metal in the external electrode may be suppressed. As a result, gaps are more likely to occur in the external electrode, thereby leading to insulation deterioration caused by moisture infiltrating during plating and remaining in the gaps.
- Preferred embodiments of the present invention provide multilayer ceramic electronic components, in each of which formation of gaps is able to be reduced or prevented by densification of metal in an external electrode even when ceramic materials as coexisting materials are dispersed in the external electrode.
- A multilayer ceramic electronic component according to a preferred embodiment of the present invention includes a multilayer body including a plurality of ceramic layers that are stacked, the multilayer body including a first main surface and a second main surface that face each other in a height direction, a first side surface and a second side surface that face each other in a width direction orthogonal or substantially orthogonal to the height direction, and a first end surface and a second end surface that face each other in a length direction orthogonal or substantially orthogonal to the height direction and the width direction; a first internal electrode layer that is disposed on each of the ceramic layers and exposed on the first end surface; a second internal electrode layer that is disposed on each of the ceramic layers and exposed on at least one surface of the second end surface, the first side surface, and the second side surface; a first external electrode that is connected to the first internal electrode layer and disposed on the first end surface; and a second external electrode that is connected to the second internal electrode layer and disposed on the at least one surface on which the second internal electrode layer is exposed. The first external electrode includes a first underlying electrode layer and a plurality of first plating layers located on the first underlying electrode layer. The second external electrode includes a second underlying electrode layer and a plurality of second plating layers located on the second underlying electrode layer. The first underlying electrode layer and the second underlying electrode layer each contain Ni as a first metal component, Sn as a second metal component, and a ceramic material, and each include an alloy portion that is provided around the ceramic material and includes an alloyed Ni defining the first metal component and an alloyed Sn defining the second metal component.
- According to preferred embodiments of the present invention, multilayer ceramic electronic components are able to be provided, in each of which formation of gaps is able to be reduced or prevented by densification of metal in an external electrode even when ceramic materials as coexisting materials are dispersed in the external electrode.
- The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.
-
FIG. 1 is an external perspective view showing an example of a multilayer ceramic capacitor according to a first preferred embodiment of the present invention. -
FIG. 2 is a cross-sectional view taken along a line II-II inFIG. 1 . -
FIG. 3 is a schematic cross-sectional view of external electrodes located on both end surfaces inFIG. 2 and regions therearound in an enlarged manner. -
FIG. 4 is a cross-sectional view taken along a line IV-IV inFIG. 1 . -
FIG. 5 is a cross-sectional view taken along a line V-V inFIG. 2 . -
FIG. 6 is a cross-sectional view taken along a line VI-VI inFIG. 2 . -
FIG. 7A is a cross-sectional view, which is taken along line II-II inFIG. 1 , showing a structure in which a facing electrode portion of an internal electrode layer of a multilayer ceramic capacitor according to a preferred embodiment of the present invention is divided into two sections. -
FIG. 7B is a cross-sectional view, which is taken along line II-II inFIG. 1 , showing a structure in which a facing electrode portion of an internal electrode layer of a multilayer ceramic capacitor according to a preferred embodiment of the present invention is divided into three sections. -
FIG. 7C is a cross-sectional view, which is taken along line II-II inFIG. 1 , showing a structure in which a facing electrode portion of an internal electrode layer of a multilayer ceramic capacitor according to a preferred embodiment of the present invention is divided into four sections. -
FIG. 8 is an external perspective view showing an example of a multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to a second preferred embodiment of the present invention. -
FIG. 9 is a top view showing an example of the multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to the second preferred embodiment of the present invention. -
FIG. 10 is a side view showing an example of the multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to the second preferred embodiment of the present invention. -
FIG. 11 is a cross-sectional view taken along a line XI-XI inFIG. 8 . -
FIG. 12 is a schematic cross-sectional view of external electrodes located on both end surfaces inFIG. 11 and regions therearound in an enlarged manner. -
FIG. 13 is a cross-sectional view taken along a line XIII-XIII inFIG. 8 . -
FIG. 14 is a schematic cross-sectional view of external electrodes located on both side surfaces inFIG. 13 and regions therearound in an enlarged manner. -
FIG. 15 is a cross-sectional view taken along a line XV-XV inFIG. 11 . -
FIG. 16 is a cross-sectional view taken along a line XVI-XVI inFIG. 11 . -
FIG. 17 shows a modification of a first internal electrode layer shown inFIG. 15 . - A multilayer ceramic capacitor will be described as an example of a multilayer ceramic electronic component according to a first preferred embodiment of the present invention.
FIG. 1 is an external perspective view showing an example of a multilayer ceramic capacitor according to the first preferred embodiment of the present invention.FIG. 2 is a cross-sectional view taken along a line II-II inFIG. 1 .FIG. 3 is a schematic cross-sectional view of external electrodes located on both end surfaces inFIG. 2 and regions therearound in an enlarged manner.FIG. 4 is a cross-sectional view taken along a line IV-IV inFIG. 1 .FIG. 5 is a cross-sectional view taken along a line V-V inFIG. 2 .FIG. 6 is a cross-sectional view taken along a line VI-VI inFIG. 2 . - As shown in
FIGS. 1 to 4 , a multilayerceramic capacitor 10 includes amultilayer body 12 having a rectangular or substantially rectangular parallelepiped shape. -
Multilayer body 12 includes a plurality of stackedceramic layers 14 and a plurality ofinternal electrode layers 16.Multilayer body 12 also includes a firstmain surface 12 a and a secondmain surface 12 b that face each other in a height direction x, afirst side surface 12 c and asecond side surface 12 d that face each other in a width direction y orthogonal or substantially orthogonal to height direction x, and afirst end surface 12 e and asecond end surface 12 f that face each other in a length direction z orthogonal or substantially orthogonal to height direction x and width direction y.Multilayer body 12 includes corner portions and ridge portions, each of which is preferably rounded. In this case, the corner portion corresponds to a portion at which three adjoining planes of the multilayer body cross each other. The ridge portion corresponds to a portion at which two adjoining planes of the multilayer body cross each other. Furthermore, firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c,second side surface 12 d,first end surface 12 e, andsecond end surface 12 f each may be partially or entirely provided with, for example, projections and recesses, and the like. - The number of
ceramic layers 14 including outer layers is preferably 15 or more and 700 or less, for example. - In the stacking direction extending along a line connecting first
main surface 12 a and secondmain surface 12 b,multilayer body 12 includes aneffective layer portion 15 a in which internal electrode layers 16 face each other, a firstouter layer portion 15 b located between firstmain surface 12 a and one of internal electrode layers 16 that is closest to firstmain surface 12 a, and a secondouter layer portion 15 c located between secondmain surface 12 b and one of internal electrode layers 16 that is closest to secondmain surface 12 b. - First
outer layer portion 15 b includes a plurality ofceramic layers 14 that are located on the firstmain surface 12 a side ofmultilayer body 12 and also located between firstmain surface 12 a and one of internal electrode layers 16 that is closest to firstmain surface 12 a. - Second
outer layer portion 15 c includes a plurality ofceramic layers 14 that are located on the secondmain surface 12 b side ofmultilayer body 12 and also located between secondmain surface 12 b and one of internal electrode layers 16 that is closest to secondmain surface 12 b. - A region sandwiched between first
outer layer portion 15 b and secondouter layer portion 15 c iseffective layer portion 15 a. - Although the dimensions of
multilayer body 12 are not particularly limited, it is preferable that, for example, the dimension ofmultilayer body 12 in length direction z is about 0.2 mm or more and about 10.0 mm or less, the dimension ofmultilayer body 12 in width direction y is about 0.1 mm or more and about 10.0 mm or less, and the dimension ofmultilayer body 12 in height direction x is about 0.1 mm or more and about 5.0 mm or less. -
Ceramic layer 14 can be made of a dielectric material such as a ceramic material, for example. Such a dielectric material can be made of dielectric ceramic containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3, for example. When the above-described dielectric material is contained as a main component, a material additionally containing a sub-component (such as an Mn compound, an Fe compound, a Cr compound, a Co compound, or an Ni compound, for example) that is less in content than the main component may be used in accordance with the desired characteristics formultilayer body 12. - When a piezoelectric ceramic is used for
multilayer body 12, the multilayer ceramic electronic component defines and functions as a ceramic piezoelectric element. A specific example of the piezoelectric ceramic material may be a lead zirconate titanate (PZT)-based ceramic material or the like. - Furthermore, when a semiconductor ceramic is used for
multilayer body 12, the multilayer ceramic electronic component defines and functions as a thermistor element. A specific example of the semiconductor ceramic material may be a spinel-based ceramic material or the like, for example. - Furthermore, when magnetic ceramic is used for
multilayer body 12, the multilayer ceramic electronic component defines and functions as an inductor element. When the multilayer ceramic electronic component defines and functions as an inductor element,internal electrode layer 16 is a coil-shaped conductor. A specific example of the magnetic ceramic material may be a ferrite ceramic material or the like, for example. - The thickness of fired
ceramic layer 14 is preferably about 0.4 μm or more and about 10.0 μm or less, for example. - As shown in
FIGS. 5 and 6 ,multilayer body 12 includes, as a plurality of internal electrode layers 16, a plurality of first internal electrode layers 16 a and a plurality of second internal electrode layers 16 b, each of which has a rectangular or approximately rectangular shape, for example. The plurality of first internal electrode layers 16 a and the plurality of second internal electrode layers 16 b are buried so as to be alternately arranged at regular intervals in the stacking direction ofmultilayer body 12. First internal electrode layers 16 a and second internal electrode layers 16 b may be disposed in parallel or substantially in parallel with a mounting surface or may be disposed to be vertical to the mounting surface. - Each first
internal electrode layer 16 a includes a first facingelectrode portion 18 a that faces secondinternal electrode layer 16 b, and a first extendingelectrode portion 20 a located on one end side of firstinternal electrode layer 16 a and extending from first facingelectrode portion 18 a tofirst end surface 12 e ofmultilayer body 12. First extendingelectrode portion 20 a includes an end portion extending tofirst end surface 12 e and exposed fromfirst end surface 12 e. - Each second
internal electrode layer 16 b includes a second facingelectrode portion 18 b that faces firstinternal electrode layer 16 a, and a second extendingelectrode portion 20 b located on one end side of secondinternal electrode layer 16 b and extending from second facingelectrode portion 18 b tosecond end surface 12 f ofmultilayer body 12. Second extendingelectrode portion 20 b includes an end portion extending tosecond end surface 12 f and exposed fromsecond end surface 12 f. - It is preferable that first facing
electrode portion 18 a of firstinternal electrode layer 16 a and second facingelectrode portion 18 b of secondinternal electrode layer 16 b each have a rectangular or substantially rectangular shape, but is not particularly limited. Also, each of corner portions of the rectangular or substantially rectangular shape may be rounded or may have an inclined shape (in a tapered shape, for example). - It is preferable that first extending
electrode portion 20 a of firstinternal electrode layer 16 a and second extendingelectrode portion 20 b of secondinternal electrode layer 16 b each have a rectangular or substantially rectangular shape, but is not particularly limited. Also, each of corner portions of the rectangular or substantially rectangular shape may be rounded or may have in an inclined shape (in a tapered shape, for example). - First facing
electrode portion 18 a of firstinternal electrode layer 16 a and first extendingelectrode portion 20 a of firstinternal electrode layer 16 a may have the same width, or one of the widths may be narrower than the other. Similarly, second facingelectrode portion 18 b of secondinternal electrode layer 16 b and second extendingelectrode portion 20 b of secondinternal electrode layer 16 b may have the same width, or one of the widths may be narrower than the other. -
Multilayer body 12 includes a side portion (W gap) 24 a provided betweenfirst side surface 12 c and one end of each of first facingelectrode portion 18 a and second facingelectrode portion 18 b in width direction y, and betweensecond side surface 12 d and the other end of each of first facingelectrode portion 18 a and second facingelectrode portion 18 b in width direction y. Furthermore,multilayer body 12 includes an end portion (L gap) 24 b provided betweensecond end surface 12 f and one end of firstinternal electrode layer 16 a that is opposite to first extendingelectrode portion 20 a, and betweenfirst end surface 12 e and one end of secondinternal electrode layer 16 b that is opposite to second extendingelectrode portion 20 b. -
Internal electrode layer 16 contains electrically conductive materials made of, for example, metals such as Ni, Cu, Ag, Pd, or Au, or an alloy such as an Ag—Pd alloy containing at least one of these metals.Internal electrode layer 16 may further contain dielectric particles of the same composition base as that of ceramic contained inceramic layer 14. -
Internal electrode layer 16 is preferably made of a material containing Ni as the third metal component and Sn as the fourth metal component. Also, Ni as the third metal component and Sn as the third metal component may also be partially alloyed. Thus, alloying of Ni and Sn changes the state (an electrical barrier height) at and around the interface ofinternal electrode layer 16 withceramic layer 14, thus contributing to an improvement in high-temperature load life. This results in multilayerceramic capacitor 10 that has excellent reliability (improved in high-temperature load life) during voltage application. The fourth metal component may be an Sn material made of, for example, any one of metal containing Sn and an Sn compound, or, in place of Sn, may be tin oxide powder represented by Sno or SnO2. - It is preferable that Ni as the third metal component is a main component while Sn as the fourth metal component is a sub-component.
- In this case, assuming that the sum of Ni as the third metal component and Sn as the fourth metal component in
internal electrode layer 16 is 100 mol, the content of Sn is preferably about 0.001 mol or more and about 0.1 mol or less, for example. When the content of Sn is about 0.001 mol or more, the effect of containing Sn is more effectively achieved. When the content of Sn is about 0.1 mol or less, the melting point ofinternal electrode layer 16 falls within a preferable range, so that problems, such as balling, are less likely to occur. The above-described state can be achieved by, adding, to an electrically conductive paste for internal electrode formation, Sn of the fourth metal component as a sub-component for Ni of the third metal component as a main component; or adding an Ni—Sn alloy to the electrically conductive paste for internal electrode formation. - As shown in
FIGS. 2 to 6 , it is preferable that the portion provided by alloying Ni as the third metal component and Sn as the fourth metal component includes analloy layer 22 provided at an interface betweenceramic layer 14 andinternal electrode layer 16 so as to coverinternal electrode layer 16.Alloy layer 22 includes afirst alloy layer 22 a and asecond alloy layer 22 b.First alloy layer 22 a covers firstinternal electrode layer 16 a, andsecond alloy layer 22 b covers secondinternal electrode layer 16 b. In this way,alloy layer 22 provided by alloying Ni and Sn is thus included to change the state (an electrical height) at and around the interface ofinternal electrode layer 16 withceramic layer 14, and thus contribute to improvement in high-temperature load life. As a result, multilayerceramic capacitor 10 having excellent reliability (improved in high-temperature load life) during voltage application is obtained. - To check
alloy layer 22, the cross section ofmultilayer body 12 is polished (for example, to expose an LT cross section at ½ W position) and thereafter checked by WDX analysis for composition differences. Then, based on the composition differences, the range ofalloy layer 22 can be specified. Furthermore, a portion of the cross section (includingceramic layer 14 and internal electrode layer 16) is sliced and then subjected to TEM analysis. Thus, the composition differences can be more specifically checked. - The thickness of
internal electrode layer 16 is preferably about 0.2 μm or more and about 2.0 μm or less, for example. Also, the number of internal electrode layers 16 is preferably 15 or more and 200 or less, for example. - An
external electrode 26 is disposed on thefirst end surface 12 e side and thesecond end surface 12 f side ofmultilayer body 12.External electrode 26 includes a firstexternal electrode 26 a and a secondexternal electrode 26 b. - First
external electrode 26 a is disposed onfirst end surface 12 e ofmultilayer body 12 and extends fromfirst end surface 12 e to partially cover each of firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. In this case, firstexternal electrode 26 a is electrically connected to first extendingelectrode portion 20 a of firstinternal electrode layer 16 a. Firstexternal electrode 26 a may be provided only onfirst end surface 12 e ofmultilayer body 12. - Second
external electrode 26 b is disposed onsecond end surface 12 f ofmultilayer body 12, and extends fromsecond end surface 12 f to partially cover each of firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. In this case, secondexternal electrode 26 b is electrically connected to second extendingelectrode portion 20 b of secondinternal electrode layer 16 b. Secondexternal electrode 26 b may be provided only onsecond end surface 12 f ofmultilayer body 12. - On the inside of
multilayer body 12, first facingelectrode portion 18 a of firstinternal electrode layer 16 a and second facingelectrode portion 18 b of secondinternal electrode layer 16 b face each other withceramic layer 14 interposed therebetween, thus generating a capacitance. Thus, a capacitance can be obtained between firstexternal electrode 26 a to which firstinternal electrode layer 16 a is connected and secondexternal electrode 26 b to which secondinternal electrode layer 16 b is connected, thus having a characteristic of a capacitor. - As
internal electrode layer 16, floating internal electrode layers 16 c not extending to either offirst end surface 12 e andsecond end surface 12 f may be provided in addition to firstinternal electrode layer 16 a and secondinternal electrode layer 16 b, as shown inFIGS. 7A to 7C , thus providing a structure in which facingelectrode portion 18 c is divided into a plurality of sections by floating internal electrode layers 16 c. Examples of the structure include a 2-stage structure as shown inFIG. 7A , a 3-stage structure as shown inFIG. 7B , a 4-stage structure as shown inFIG. 7C , and 5-or-more-stage structure. The structure including facingelectrode portion 18 c divided into a plurality of sections in this way enables to a configuration in which a plurality of capacitor components are provided between internal electrode layers 16 a, 16 b, and 16 c facing each other and these capacitor components are connected in series. Thus, a relatively low voltage is applied to each capacitor component, so that the multilayer ceramic capacitor can have an increased breakdown voltage. -
External electrode 26 includes an underlying electrode layer 28 disposed on the surface ofmultilayer body 12, and aplating layer 30 covering underlying electrode layer 28. - Underlying electrode layer 28 includes a first
underlying electrode layer 28 a and a secondunderlying electrode layer 28 b. - First
underlying electrode layer 28 a is disposed onfirst end surface 12 e ofmultilayer body 12, and extends fromfirst end surface 12 e to partially cover each of firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. - Second
underlying electrode layer 28 b is disposed onsecond end surface 12 f ofmultilayer body 12, and extends fromsecond end surface 12 f to partially cover each of firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. - First
underlying electrode layer 28 a may be disposed only onfirst end surface 12 e ofmultilayer body 12, and secondunderlying electrode layer 28 b may be disposed only onsecond end surface 12 f ofmultilayer body 12. - It is preferable that first
underlying electrode layer 28 a located onfirst end surface 12 e and secondunderlying electrode layer 28 b located onsecond end surface 12 f each are, for example, about 3 μm or more and about 160 μm or less in thickness in a center portion in the stacking direction. - When underlying electrode layer 28 is provided on each of first
main surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d, a thickness is preferably, for example, about 3 μm or more and about 40 μm or less in the center portion in length direction z in each of firstunderlying electrode layer 28 a and secondunderlying electrode layer 28 b that are located on each of firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. - Underlying electrode layer 28 (first
underlying electrode layer 28 a and secondunderlying electrode layer 28 b) contains Ni as the first metal component, Sn as the second metal component, and ceramic particles (a ceramic material). Underlying electrode layer 28 also includes a portion provided by alloying Ni as the first metal component and Sn as the second metal component. Thus, Ni as the first metal component and Sn as the second metal component in underlying electrode layer 28 are partially alloyed to lower the melting point. Accordingly, the sinterability of underlying electrode layer 28 can be improved, and the reaction of the alloy in underlying electrode layer 28 is activated. Thus, densification of underlying electrode layer 28 progresses. As a result, formation of gaps that may occur inside underlying electrode layer 28 can be reduced or prevented. In view of the above, multilayerceramic capacitor 10 enables reduction or prevention of formation of gaps through which moisture infiltrates during formation of a plating layer and the like. Thus, moisture does not infiltrate into each external electrode, and also, moisture can be prevented from infiltrating intomultilayer body 12, with the result that insulation deterioration can be prevented. - In this case, it is preferable that Ni as the first metal component is a main component, and Sn as the second metal component is a sub-component.
- Also as shown in
FIG. 3 , ceramic particles (ceramic material) 38 randomly exist in firstunderlying electrode layer 28 a and secondunderlying electrode layer 28 b, each of which is made of Ni. Also, analloy portion 40 is provided that is formed by alloying Ni as the first metal component and Sn as the second metal component so as to surround each ofceramic particles 38. -
Alloy portion 40 in underlying electrode layer 28 is checked by the following method. Specifically, platinglayer 30 of multilayerceramic capacitor 10 is first peeled off to expose underlying electrode layer 28. Then, XRD analysis is conducted on the end surface of the exposed underlying electrode layer 28 to extract only peaks of Ni. Thus, it can be checked that the peak position of Ni in the portion containing Sn is shifted to the low angle side with respect to the portion not containing Sn, and thus, it can be determined that Ni is partially alloyed. - Also, the
alloy portion 40 may exist entirely aroundceramic particle 38 or may exist on only a portion ofceramic particle 38. - Furthermore,
ceramic particles 38 may be partially in contact with each other withalloy portion 40 interposed therebetween, or may be space apart and contacting each other. - Also at the interface between underlying electrode layer 28 and
multilayer body 12, an endsurface alloy layer 42 is provided that is formed by alloying Ni as the first metal component and Sn as the second metal component contained in underlying electrode layer 28, or by alloying Ni as the third metal component contained ininternal electrode layer 16 and Sn as the second metal component contained in underlying electrode layer 28. - End
surface alloy layer 42 includes a first endsurface alloy layer 42 a and a second endsurface alloy layer 42 b. First endsurface alloy layer 42 a is disposed at the interface betweenfirst end surface 12 e ofmultilayer body 12 and firstunderlying electrode layer 28 a. Second endsurface alloy layer 42 b is disposed at the interface betweensecond end surface 12 f ofmultilayer body 12 and secondunderlying electrode layer 28 b. - When Sn as the fourth metal component is added to
internal electrode layer 16, Ni as the third metal component ofinternal electrode layer 16 may be alloyed with Sn as the fourth metal component. In other words, at the interface between underlying electrode layer 28 andmultilayer body 12, endsurface alloy layer 42 may be provided that is made of the first metal component to the fourth metal component contained in each ofinternal electrode layer 16 and underlying electrode layer 28. - First end
surface alloy layer 42 a disposed at the interface between firstunderlying electrode layer 28 a andmultilayer body 12 may be disposed at the entire interface between firstunderlying electrode layer 28 a andmultilayer body 12, or may be disposed at a portion of the interface between firstunderlying electrode layer 28 a andmultilayer body 12. Furthermore, second endsurface alloy layer 42 b disposed at the interface between secondunderlying electrode layer 28 b andmultilayer body 12 may be disposed at the entire interface between secondunderlying electrode layer 28 b andmultilayer body 12, or may be disposed at a portion of the interface between secondunderlying electrode layer 28 b andmultilayer body 12. - Thus, since end
surface alloy layer 42 is disposed at the interface between underlying electrode layer 28 andmultilayer body 12 in this way, the melting point at and around each of both end surfaces ofmultilayer body 12 can be lowered. Consequently, the sinterability ofceramic layer 14 located near each the end surfaces of themultilayer body 12 can be more effectively improved. - As to the amounts of Ni as the first metal component, Sn as the second metal component, and ceramic particles (a ceramic material) contained in underlying electrode layer 28, for example, assuming that the sum of Ni as the first metal component and Sn as the second metal component is 100 mol, the content of Sn is preferably about 0.001 mol or more and about 0.1 mol or less, and the content of the ceramic particles (a ceramic material) is preferably about 5% or more and about 50% or less with respect to the entire volume of underlying electrode layer 28.
- It is preferable that the dielectric material as a ceramic material contained in underlying electrode layer 28 includes at least one selected from BaTiO3, CaTiO3, SrTiO3, or CaZrO3, for example. Since the dielectric material is contained as a coexisting material in underlying electrode layer 28, the dielectric material contained in underlying electrode layer 28 reacts with
ceramic layer 14 in each of firstouter layer portion 15 b and secondouter layer portion 15 c ofmultilayer body 12, to thus achieve an anchor effect. Consequently, the adhesive force between underlying electrode layer 28 andmultilayer body 12 is improved. - When piezoelectric ceramic is used for
multilayer body 12, examples of the piezoelectric ceramic material as a ceramic material contained in underlying electrode layer 28 may be a PZT (lead zirconate titanate)-based ceramic material and the like. - When semiconductor ceramic is used for
multilayer body 12, examples of the semiconductor ceramic material as a ceramic material contained in underlying electrode layer 28 may be a spinel-based ceramic material, and the like. - When magnetic ceramic is used for
multilayer body 12, examples of the magnetic ceramic material as a ceramic material contained in underlying electrode layer 28 may be a ferrite ceramic material and the like. - Plating
layer 30 includes afirst plating layer 30 a and asecond plating layer 30 b. - First plating
layer 30 a is disposed to cover firstunderlying electrode layer 28 a. -
Second plating layer 30 b is disposed to cover secondunderlying electrode layer 28 b. - Plating
layer 30 preferably contains at least one selected, for example, from Cu, Ni, Sn, Ag, Pd, an Ag—Pd alloy, Au, and the like. - Plating
layer 30 may include a plurality of layers. - Preferably, plating
layer 30 includes a lower plating layer 32 covering underlying electrode layer 28, an intermediate plating layer 34 covering lower plating layer 32; and an upper plating layer 36 covering intermediate plating layer 34. - The thickness of one plating layer is preferably about 1 μm or more and about 15 μm or less, for example.
- Lower plating layer 32 includes a first
lower plating layer 32 a and a secondlower plating layer 32 b. - First
lower plating layer 32 a covers firstunderlying electrode layer 28 a. Specifically, it is preferable that firstlower plating layer 32 a is disposed on the surface of firstunderlying electrode layer 28 a that is located onfirst end surface 12 e, so as to also extend to the surface of firstunderlying electrode layer 28 a that is located on firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. Firstlower plating layer 32 a may be disposed only on the surface of firstunderlying electrode layer 28 a disposed onfirst end surface 12 e. - Second
lower plating layer 32 b to covers secondunderlying electrode layer 28 b. Specifically, it is preferable that secondlower plating layer 32 b is disposed on the surface of secondunderlying electrode layer 28 b that is located onsecond end surface 12 f, so as to also extend to the surface of secondunderlying electrode layer 28 b that is located on firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. Secondlower plating layer 32 b may be disposed only on the surface of secondunderlying electrode layer 28 b disposed onsecond end surface 12 f. - In the present preferred embodiment, lower plating layer 32 is preferably defined by a Cu plating layer, for example. Lower plating layer 32 is defined by a Cu plating layer and covers the surface of underlying electrode layer 28, thus achieving an effect of reducing or preventing infiltration of a plating solution.
- The stress of the Cu plating layer applied to the multilayer body is preferably about −400 MPa or more and about −3 MPa or less, for example. Thus, the compressive stress of the Cu plating layer may reduce the tensile stress to be applied to the end portion of underlying electrode layer 28 after multilayer
ceramic capacitor 10 is mounted on a mounting substrate, with the result that the effect of improving the mechanical strength is achieved. - Intermediate plating layer 34 includes a first
intermediate plating layer 34 a and a secondintermediate plating layer 34 b. - First
intermediate plating layer 34 a covers firstlower plating layer 32 a. Specifically, it is preferable that firstintermediate plating layer 34 a is disposed on the surface of firstlower plating layer 32 a that is located onfirst end surface 12 e so as to also extend to the surface of firstlower plating layer 32 a that is located on firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. Firstintermediate plating layer 34 a may be disposed only on the surface of firstlower plating layer 32 a disposed onfirst end surface 12 e. - Second
intermediate plating layer 34 b covers secondlower plating layer 32 b. Specifically, it is preferable that secondintermediate plating layer 34 b is disposed on the surface of secondlower plating layer 32 b that is located onsecond end surface 12 f so as to also extend to the surface of secondlower plating layer 32 b that is located on firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. It should be noted that secondintermediate plating layer 34 b may be disposed only on the surface of secondlower plating layer 32 b disposed onsecond end surface 12 f. - In the present preferred embodiment, intermediate plating layer 34 is preferably defined by an Ni plating layer, for example. Intermediate plating layer 34 is defined an Ni plating layer and covers the surface of lower plating layer 32. As a result, underlying electrode layer 28 can be prevented from being eroded by solder used when multilayer
ceramic capacitor 10 is mounted on a mounting substrate. - Upper plating layer 36 includes a first
upper plating layer 36 a and a secondupper plating layer 36 b. - First
upper plating layer 36 a covers firstintermediate plating layer 34 a. Specifically, it is preferable that firstupper plating layer 36 a is disposed on the surface of firstintermediate plating layer 34 a that is located onfirst end surface 12 e, so as to also extend to the surface of firstintermediate plating layer 34 a that is located on firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. Firstupper plating layer 36 a may be disposed only on the surface of firstintermediate plating layer 34 a disposed onfirst end surface 12 e. - Second
upper plating layer 36 b covers secondintermediate plating layer 34 b. Specifically, it is preferable that secondupper plating layer 36 b is disposed on the surface of secondintermediate plating layer 34 b that is located onsecond end surface 12 f, so as to also extend to the surface of secondintermediate plating layer 34 b that is located on firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. Secondupper plating layer 36 b may be disposed only on the surface of secondintermediate plating layer 34 b disposed onsecond end surface 12 f. - In the present preferred embodiment, upper plating layer 36 is preferably defined by an Sn plating layer, for example. Upper plating layer 36 is defined by an Sn plating layer and covers the surface of intermediate plating layer 34, to thus improve the wettability of solder used when multilayer
ceramic capacitor 10 is mounted on a mounting substrate, with the result that multilayerceramic capacitor 10 can be readily mounted. - In
external electrode 26 according to the present preferred embodiment, platinglayer 30 includes three layers including lower plating layer 32, intermediate plating layer 34, and upper plating layer 36, but the present invention is not limited thereto, and may include only lower plating layer 32, may include only of intermediate plating layer 34, or may include only of upper plating layer 36. - In addition, multilayer
ceramic capacitor 10 includingmultilayer body 12, firstexternal electrode 26 a, and secondexternal electrode 26 b has a dimension in length direction Z defined as an L dimension, a dimension in height direction X defined as a T dimension, and a dimension in width direction y defined as a W dimension. - As to the dimensions of multilayer
ceramic capacitor 10, it is preferable that the L dimension in length direction z is about 0.20 mm or more and about 10.0 mm or less, the W dimension in width direction y is about 0.10 mm or more and about 10.0 mm or less, and the T dimension in height direction x is about 0.10 mm or more and about 5.0 mm or less, for example. - In multilayer
ceramic capacitor 10 shown inFIG. 1 , underlying electrode layer 28 contains Ni as the first metal component, Sn as the second metal component, and ceramic particles (a ceramic material). Thus, by containing Ni as the first metal component and Sn as the second metal component in this way, Ni as the first metal component and Sn as the second metal component in underlying electrode layer 28 are partially alloyed to lower the melting point. Accordingly, the sinterability of underlying electrode layer 28 can be improved to thus activate the reaction of the alloy in underlying electrode layer 28, and thus, densification ofexternal electrode 26 progresses. As a result, formation of gaps that may occur in underlying electrode layer 28 can be reduced or prevented. - Therefore, multilayer
ceramic capacitor 10 shown inFIG. 1 enables reduction or prevention of occurrence of gaps through which moisture infiltrates during formation of a plating layer or the like. Accordingly, moisture does not infiltrate into each external electrode, and thus, moisture can be prevented from infiltrating also intomultilayer body 12, so that insulation deterioration can be prevented. As a result, multilayerceramic capacitor 10 can be improved in reliability. - In the following, a multilayer ceramic capacitor will be described as an example of a multilayer ceramic electronic component according to a second preferred embodiment of the present invention. The multilayer ceramic capacitor according to the present second preferred embodiment is a three-terminal multilayer ceramic capacitor.
- Referring to
FIG. 8 , a multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) will be described as an example of the multilayer ceramic electronic component according to the second preferred embodiment of the present invention.FIG. 8 is an external perspective view showing an example of a multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to the second preferred embodiment of the present invention.FIG. 9 is a top view showing an example of the multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to the second preferred embodiment of the present invention.FIG. 10 is a side view showing an example of the multilayer ceramic capacitor (a three-terminal multilayer ceramic capacitor) according to the second preferred embodiment of the present invention.FIG. 11 is a cross-sectional view taken along a line XI-XI inFIG. 8 .FIG. 12 is a schematic cross-sectional view of external electrodes located on both end surfaces inFIG. 11 and regions therearound in an enlarged manner.FIG. 13 is a cross-sectional view taken along a line XIII-XIII inFIG. 8 .FIG. 14 is a schematic cross-sectional view of external electrodes located on both side surfaces inFIG. 13 and regions therearound in an enlarged manner.FIG. 15 is a cross-sectional view taken along a line XV-XV inFIG. 11 .FIG. 16 is a cross-sectional view taken along a line XVI-XVI inFIG. 11 . - As shown in
FIGS. 8 to 13 , a multilayerceramic capacitor 110 includes amultilayer body 12 having a rectangular or substantially rectangular parallelepiped shape, for example. -
Multilayer body 12 includes a plurality of stackedceramic layers 14 and a plurality of internal electrode layers 116.Multilayer body 12 also includes a firstmain surface 12 a and a secondmain surface 12 b that face each other in a height direction x, afirst side surface 12 c and asecond side surface 12 d that face each other in a width direction y orthogonal or substantially orthogonal to height direction x, and afirst end surface 12 e and asecond end surface 12 f that face each other in a length direction z orthogonal or substantially orthogonal to height direction x and width direction y. Thismultilayer body 12 includes corner portions and ridge portions, each of which is preferably rounded. In this case, the corner portion corresponds to a portion at which three adjoining planes of the multilayer body cross each other. The ridge portion corresponds to a portion at which two adjoining planes of the multilayer body cross each other. Furthermore, firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c,second side surface 12 d,first end surface 12 e, andsecond end surface 12 f each may be partially or entirely provided with, for example, projections and recesses, and the like. The dimension ofmultilayer body 12 in length direction z is not necessarily longer than the dimension ofmultilayer body 12 in width direction y. - In the stacking direction extending along a line connecting first
main surface 12 a and secondmain surface 12 b,multilayer body 12 includes aneffective layer portion 15 a in which internal electrode layers 116 face each other, a firstouter layer portion 15 b located between firstmain surface 12 a and one of internal electrode layers 116 that is closest to firstmain surface 12 a, and a secondouter layer portion 15 c located between secondmain surface 12 b and one of internal electrode layers 116 that is closest to secondmain surface 12 b. - First
outer layer portion 15 b includes a plurality ofceramic layers 14 that are located on the firstmain surface 12 a side ofmultilayer body 12 and also located between firstmain surface 12 a and one of internal electrode layers 116 that is closest to firstmain surface 12 a. - Second
outer layer portion 15 c includes a plurality ofceramic layers 14 that are located on the secondmain surface 12 b side ofmultilayer body 12 and also located between secondmain surface 12 b and one of internal electrode layers 116 that is closest to secondmain surface 12 b. - A region sandwiched between first
outer layer portion 15 b and secondouter layer portion 15 c iseffective layer portion 15 a. - Since
ceramic layer 14 is made of the same or substantially the same material as that of multilayerceramic capacitor 10, the description thereof will not be repeated. - Also, since the average thickness of the fired
ceramic layers 14 in the stacking direction is the same or substantially the same as that of multilayerceramic capacitor 10, the description thereof will not be repeated. -
Multilayer body 12 includes, as a plurality of internal electrode layers 116, a plurality of first internal electrode layers 116 a and a plurality of second internal electrode layers 116 b. The plurality of first internal electrode layers 116 a and the plurality of second internal electrode layers 116 b are buried so as to be alternately arranged at regular intervals in the stacking direction ofmultilayer body 12. - As shown in
FIG. 15 , firstinternal electrode layer 116 a includes a first facingelectrode portion 118 a that faces secondinternal electrode layer 116 b, one first extending electrode portion 120 al extending from first facingelectrode portion 118 a tofirst end surface 12 e ofmultilayer body 12, and the other second extending electrode portion 120 a 2 extending from first facingelectrode portion 118 a tosecond end surface 12 f ofmultilayer body 12. Specifically, one first extending electrode portion 120 al is exposed onfirst end surface 12 e ofmultilayer body 12 while the other first extending electrode portion 120 a 2 is exposed onsecond end surface 12 f ofmultilayer body 12. Thus, firstinternal electrode layer 116 a is not exposed onfirst side surface 12 c andsecond side surface 12 d ofmultilayer body 12. - As shown in
FIG. 16 , secondinternal electrode layer 116 b has an approximately cross shape, and includes a second facingelectrode portion 118 b that faces firstinternal electrode layer 116 a, one second extending electrode portion 120 b 1 extending from second facingelectrode portion 118 b tofirst side surface 12 c ofmultilayer body 12, and the other second extending electrode portion 120 b 2 extending from second facingelectrode portion 118 b tosecond side surface 12 d ofmultilayer body 12. Specifically, one second extending electrode portion 120 b 1 is exposed onfirst side surface 12 c ofmultilayer body 12 while the other second extending electrode portion 120 b 2 is exposed onsecond side surface 12 d ofmultilayer body 12. Thus, secondinternal electrode layer 116 b is not exposed onfirst end surface 12 e andsecond end surface 12 f ofmultilayer body 12. - Four corner portions of second facing
electrode portion 118 b in secondinternal electrode layer 116 b are not chamfered, but may be chamfered. This can prevent overlapping between the four corner portions of second facingelectrode portion 118 b and the corner portions of first facingelectrode portion 118 a in firstinternal electrode layer 116 a, and thus, any electric field concentration can be reduced or prevented. As a result, any electric breakdown in the ceramic capacitor that may be caused by electric field concentration can be reduced or prevented. - Furthermore,
multilayer body 12 includes a side portion (hereinafter also referred to as a “W gap”) 24 a provided betweenfirst side surface 12 c and one end of first facingelectrode portion 118 a of firstinternal electrode layer 116 a in width direction y, and betweensecond side surface 12 d and the other end of first facingelectrode portion 118 a of firstinternal electrode layer 116 a in width direction y, and also includesside portion 24 a provided betweenfirst side surface 12 c and one end of second facingelectrode portion 118 b of secondinternal electrode layer 116 b in width direction y, and betweensecond side surface 12 d and the other end of first facingelectrode portion 118 a of secondinternal electrode layer 116 b in width direction y. Furthermore,multilayer body 12 includes an end portion (hereinafter also referred to as an “L gap”) 24 b provided betweenfirst end surface 12 e and one end of secondinternal electrode layer 116 b in length direction z, and betweensecond end surface 12 f and the other end of secondinternal electrode layer 116 b in length direction z. - It is preferable that
internal electrode layer 116 contains Ni as the third metal component and Sn as the fourth metal component. Also, Ni as the third metal component and Sn as the third metal component may be partially alloyed. Thus, alloying of Ni and Sn changes the state (an electrical barrier height) at and around the interface ofinternal electrode layer 116 withceramic layer 14, thus contributing to an improvement in high-temperature load life. As a result, multilayerceramic capacitor 10 having excellent reliability (improved in high-temperature load life) during voltage application is obtained. - In this case, it is preferable that Ni as the third metal component is a main component and Sn as the fourth metal component is a sub-component.
- In this case, assuming that the sum of Ni as the third metal component and Sn as the fourth metal component in
internal electrode layer 116 is 100 mol, the content of Sn is preferably about 0.001 mol or more and about 0.1 mol or less, for example. Furthermore, the above-described state can be achieved by adding, to a paste for an internal electrode, Sn of the fourth metal component as a sub-component for Ni of the third metal component as a main component, or by adding an Ni—Sn alloy to the paste for an internal electrode. - Furthermore, it is preferable that a portion provided by alloying Ni as the third metal component and Sn as the fourth metal component includes an alloy layer 122 provided at an interface between
ceramic layer 14 andinternal electrode layer 116 so as to coverinternal electrode layer 116. Alloy layer 122 includes afirst alloy layer 122 a and asecond alloy layer 122 b.First alloy layer 122 a covers firstinternal electrode layer 116 a whilesecond alloy layer 122 b covers secondinternal electrode layer 116 b. - As shown in
FIG. 17 , firstinternal electrode layer 116 a may be provided such that the width of one first extending electrode portion 120 al of firstinternal electrode layer 116 a, which extends tofirst end surface 12 e, tapers towardfirst end surface 12 e, and such that the width of the other first extending electrode portion 120 a 2 of firstinternal electrode layer 116 a, which extends tosecond end surface 12 f, tapers towardsecond end surface 12 f (a tapered shape). At the position where these widths taper, the plane of first facingelectrode portion 118 a of firstinternal electrode layer 116 a and the plane of second facingelectrode portion 118 b of secondinternal electrode layer 116 b, which face each other, are preferably ensured to have at least the same or substantially the same area. - Also, an
external electrode 26 is disposed on each of thefirst end surface 12 e side, thesecond end surface 12 f side, thefirst side surface 12 c side, and thesecond side surface 12 d side ofmultilayer body 12.External electrode 26 includes a firstexternal electrode 26 a, a secondexternal electrode 26 b, a thirdexternal electrode 26 c, and a fourthexternal electrode 26 d. - First
external electrode 26 a is disposed onfirst end surface 12 e ofmultilayer body 12. Firstexternal electrode 26 a extends fromfirst end surface 12 e ofmultilayer body 12 so as to partially cover each of firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. Firstexternal electrode 26 a is electrically connected to one first extending electrode portion 120 al of firstinternal electrode layer 116 that is exposed onfirst end surface 12 e ofmultilayer body 12. - Second
external electrode 26 b is disposed onsecond end surface 12 f ofmultilayer body 12. Secondexternal electrode 26 b extends fromsecond end surface 12 f ofmultilayer body 12 so as to partially cover each of firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. Secondexternal electrode 26 b is electrically connected to the other first extending electrode portion 120 a 2 of firstinternal electrode layer 116 that is exposed onsecond end surface 12 f ofmultilayer body 12. - Third
external electrode 26 c is disposed onfirst side surface 12 c ofmultilayer body 12. Thirdexternal electrode 26 c extends fromfirst side surface 12 c so as to partially cover each of firstmain surface 12 a and secondmain surface 12 b. Thirdexternal electrode 26 c is electrically connected to one second extending electrode portion 120 b 1 of secondinternal electrode layer 116 b that is exposed onfirst side surface 12 c ofmultilayer body 12. - Fourth
external electrode 26 d is disposed onsecond side surface 12 d ofmultilayer body 12. Fourthexternal electrode 26 d extend fromsecond side surface 12 d so as to partially cover each of firstmain surface 12 a and secondmain surface 12 b. Fourthexternal electrode 26 d is electrically connected to the other second extending electrode portion 120 b 2 of secondinternal electrode layer 116 b that is exposed onsecond side surface 12 d ofmultilayer body 12. - On the inside of
multilayer body 12, first facingelectrode portion 118 a of firstinternal electrode layer 116 a and second facingelectrode portion 118 b of secondinternal electrode layer 116 b face each other with aceramic layer 14 interposed therebetween, thus generating a capacitance. Thus, a capacitance can be obtained between firstexternal electrode 26 a and secondexternal electrode 26 b to which firstinternal electrode layer 116 a is connected, and thirdexternal electrode 26 c and fourthexternal electrode 26 d to which secondinternal electrode layer 116 b is connected, thus obtaining a characteristic of a capacitor. -
External electrode 26 includes an underlying electrode layer 28 disposed on the surface ofmultilayer body 12, and aplating layer 30 covering underlying electrode layer 28. - Underlying electrode layer 28 includes a first
underlying electrode layer 28 a, a secondunderlying electrode layer 28 b, a thirdunderlying electrode layer 28 c, and a fourthunderlying electrode layer 28 d. - First
underlying electrode layer 28 a is disposed onfirst end surface 12 e ofmultilayer body 12 and extends fromfirst end surface 12 e so as to partially cover each of firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. - Second
underlying electrode layer 28 b is disposed onsecond end surface 12 f ofmultilayer body 12 and extends fromsecond end surface 12 f so as to partially cover each of firstmain surface 12 a, secondmain surface 12 b,first side surface 12 c, andsecond side surface 12 d. - First
underlying electrode layer 28 a may be disposed only onfirst end surface 12 e ofmultilayer body 12, and secondunderlying electrode layer 28 b may be disposed only onsecond end surface 12 f ofmultilayer body 12. - Third
underlying electrode layer 28 c is disposed onfirst side surface 12 c ofmultilayer body 12 and extends fromfirst side surface 12 c so as to partially cover each of firstmain surface 12 a and secondmain surface 12 b. - Fourth
underlying electrode layer 28 d is disposed onsecond side surface 12 d ofmultilayer body 12 and extends fromsecond side surface 12 d so as to partially cover each of firstmain surface 12 a and secondmain surface 12 b. - Third
underlying electrode layer 28 c may be disposed only onfirst side surface 12 c ofmultilayer body 12, and fourthunderlying electrode layer 28 d may be disposed only onsecond side surface 12 d ofmultilayer body 12. - Underlying electrode 28 layer (first
underlying electrode layer 28 a, secondunderlying electrode layer 28 b, thirdunderlying electrode layer 28 c, and fourthunderlying electrode layer 28 d) contains Ni as the first metal component, Sn as the second metal component, and ceramic particles (a ceramic material). Underlying electrode layer 28 also includes a portion formed by alloying Ni as the first metal component and Sn as the second metal component. Thus, Ni as the first metal component and Sn as the second metal component in underlying electrode layer 28 are partially alloyed, to thus lower the melting point. Accordingly, the sinterability of underlying electrode layer 28 can be improved, the reaction of the alloy in underlying electrode layer 28 is activated, and thus, densification of underlying electrode layer 28 progresses. As a result, formation of gaps that may occur in underlying electrode layer 28 can be reduced or prevented. In view of the above, multilayerceramic capacitor 10 enables reduction or prevention of formation of gaps through which moisture infiltrates during formation of a plating layer or the like. Thus, moisture does not infiltrate into each external electrode, and also, moisture can be prevented from infiltrating also intomultilayer body 12, with the result that insulation deterioration can be prevented. - In this case, it is preferable that Ni as the first metal component is a main component while Sn as the second metal component is a sub-component.
- As shown in
FIG. 12 , ceramic particles (a ceramic material) 38 randomly exist in firstunderlying electrode layer 28 a and secondunderlying electrode layer 28 b, each of which is made of Ni, and each include analloy portion 40 formed by alloying Ni as the first metal component and Sn as the second metal component such that eachalloy portion 40 surrounds correspondingceramic particle 38. - Similarly, as shown in
FIG. 14 ,ceramic particles 38 randomly exist in thirdunderlying electrode layer 28 c and fourthunderlying electrode layer 28 d, each of which is made of Ni, and each includealloy portion 40 formed by alloying Ni as the first metal component and Sn as the second metal component such that eachalloy portion 40 surrounds correspondingceramic particle 38. - Also, the
alloy portion 40 may exist entirely aroundceramic particle 38 or may exist on only a portion ofceramic particle 38. - Furthermore,
ceramic particles 38 may be partially in contact with each other withalloy portion 40 interposed therebetween, or may be spaced apart without contacting each other. - Also at the interface between underlying electrode layer 28 and
multilayer body 12, an endsurface alloy layer 42 and a sidesurface alloy layer 44 are provided, each of which is formed by alloying Ni as the first metal component and Sn as the second metal component contained in underlying electrode layer 28, or by alloying Ni as the third metal component contained ininternal electrode layer 16 and Sn as the second metal component contained in underlying electrode layer 28. - End
surface alloy layer 42 includes a first endsurface alloy layer 42 a and a second endsurface alloy layer 42 b. First endsurface alloy layer 42 a is disposed at the interface betweenfirst end surface 12 e ofmultilayer body 12 and firstunderlying electrode layer 28 a. Second endsurface alloy layer 42 b is disposed at the interface betweensecond end surface 12 f ofmultilayer body 12 and secondunderlying electrode layer 28 b. - Side
surface alloy layer 44 includes a first sidesurface alloy layer 44 a and a second sidesurface alloy layer 44 b. First sidesurface alloy layer 44 a is disposed at the interface betweenfirst side surface 12 c ofmultilayer body 12 and thirdunderlying electrode layer 28 c. Second sidesurface alloy layer 44 b is disposed at the interface betweensecond side surface 12 d ofmultilayer body 12 and fourthunderlying electrode layer 28 d. - When Sn as the fourth metal component is added to
internal electrode layer 116, Ni as the third metal component and Sn as the fourth metal component ininternal electrode layer 116 may be alloyed. In other words, at the interface between underlying electrode layer 28 andmultilayer body 12, endsurface alloy layer 42 and sidesurface alloy layer 44 may be provided, each of which includes the first metal component to the fourth metal component contained in each ofinternal electrode layer 116 and underlying electrode layer 28. - First end
surface alloy layer 42 a disposed at the interface between firstunderlying electrode layer 28 a andmultilayer body 12 may be disposed at the entire interface between firstunderlying electrode layer 28 a andmultilayer body 12, or may be disposed at a portion of the interface between firstunderlying electrode layer 28 a andmultilayer body 12. Second endsurface alloy layer 42 b disposed at the interface between secondunderlying electrode layer 28 b andmultilayer body 12 may be disposed at the entire interface between secondunderlying electrode layer 28 b andmultilayer body 12, or may be disposed at a portion of the interface between secondunderlying electrode layer 28 b andmultilayer body 12. - Furthermore, first side
surface alloy layer 44 a disposed at the interface between thirdunderlying electrode layer 28 c andmultilayer body 12 may be disposed at the entire interface between thirdunderlying electrode layer 28 c andmultilayer body 12, or may be disposed at a portion of the interface between thirdunderlying electrode layer 28 c andmultilayer body 12. Second sidesurface alloy layer 44 b disposed at the interface between fourthunderlying electrode layer 28 d andmultilayer body 12 may be disposed at the entire interface between fourthunderlying electrode layer 28 d andmultilayer body 12, or may be disposed at a portion of the interface between fourthunderlying electrode layer 28 d andmultilayer body 12. - Plating
layer 30 includes afirst plating layer 30 a, asecond plating layer 30 b, athird plating layer 30 c, and afourth plating layer 30 d. - First plating
layer 30 a is disposed to cover firstunderlying electrode layer 28 a. -
Second plating layer 30 b is disposed to cover secondunderlying electrode layer 28 b. -
Third plating layer 30 c is disposed to cover thirdunderlying electrode layer 28 c. -
Fourth plating layer 30 d is disposed to cover fourthunderlying electrode layer 28 d. - Plating
layer 30 may include a plurality of layers. - Preferably, plating
layer 30 includes a lower plating layer 32 covering underlying electrode layer 28, an intermediate plating layer 34 disposed to cover lower plating layer 32, and an upper plating layer 36 disposed to cover intermediate plating layer 34. - More specifically,
first plating layer 30 a includes a firstlower plating layer 32 a covering firstunderlying electrode layer 28 a, a firstintermediate plating layer 34 a covering firstlower plating layer 32 a, and a firstupper plating layer 36 a covering firstintermediate plating layer 34 a. -
Second plating layer 30 b includes a secondlower plating layer 32 b covering secondunderlying electrode layer 28 b, a secondintermediate plating layer 34 b covering secondlower plating layer 32 b, and a secondupper plating layer 36 b covering secondintermediate plating layer 34 b. -
Third plating layer 30 c includes a thirdlower plating layer 32 c covering thirdunderlying electrode layer 28 c, a thirdintermediate plating layer 34 c covering thirdlower plating layer 32 c, and a thirdupper plating layer 36 c covering thirdintermediate plating layer 34 c. -
Fourth plating layer 30 d includes a fourthlower plating layer 32 d covering fourthunderlying electrode layer 28 d, a fourthintermediate plating layer 34 d covering fourthlower plating layer 32 d, and a fourthupper plating layer 36 d covering fourthintermediate plating layer 34 d. - Since the material, the structure, and the like of plating
layer 30 in multilayerceramic capacitor 110 are the same or substantially the same as those of multilayerceramic capacitor 10, the description thereof will not be repeated. - A non-limiting example of a method of manufacturing a multilayer ceramic capacitor as a multilayer ceramic electronic component will be described. In the following, the method of manufacturing a multilayer ceramic capacitor according to the first preferred embodiment will be described.
- First, a ceramic paste containing ceramic powder is applied in a sheet shape, for example, by screen printing or the like, and then dried to produce a ceramic green sheet.
- Then, an electrically conductive paste for internal electrode formation is prepared and applied in a prescribed pattern on the ceramic green sheet, for example, by screen printing or gravure printing, thereby preparing a ceramic green sheet on which a conductive pattern for internal electrode formation is formed, and a ceramic green sheet on which no conductive pattern for internal electrode formation is formed.
- In this case, when Sn as the fourth metal component of a sub-component for Ni as the third metal component of a main component is contained in the metal component of the internal electrode layer, Sn as the fourth metal component of a sub-component for Ni as the third metal component of a main component of the electrically conductive paste for internal electrode formation is added to the electrically conductive paste for internal electrode formation, or an Ni—Sn alloy is added to the electrically conductive paste for internal electrode formation. In this case, as to the addition amounts of Ni as the third metal component and Sn as the fourth metal component, the content of Sn is adjusted between about 0.001 mol or more and about 0.1 mol or less, for example, assuming that the sum of Ni as the third metal component and Sn as the fourth metal component is about 100 mol.
- In addition, a ceramic paste and an electrically conductive paste for internal electrode formation may contain a known organic binder or a known organic solvent, for example.
- Then, ceramic green sheets for outer layers are prepared, on which no conductive pattern for internal electrode formation is formed. Then, a prescribed number of these ceramic green sheets for outer layers are stacked, on which ceramic green sheets on which conductive patterns for internal electrode formation are formed are sequentially stacked, and further, a prescribed number of ceramic green sheets on which no conductive pattern for internal electrode formation is formed are stacked, to thus produce a mother multilayer body. In this case, a plurality of ceramic green sheets on which conductive patterns for internal electrode formation are printed are stacked such that extending portions of the conductive patterns for internal electrode formation extend alternately toward the opposite sides, thus producing a multilayer sheet.
- Then, this multilayer sheet is press-fitted in the stacking direction by, for example, hydrostatic pressing or the like to thus produce a multilayer block.
- Then, the multilayer block is cut into a prescribed shape and dimension so as to cut out a raw multilayer body chip. On this occasion, barrel polishing or the like, for example, may be provided to the raw multilayer body chip such that corner portions and ridge portions are rounded.
- Then, underlying electrode layer 28 is formed. First, by methods such as dipping or screen printing, for example, both end surfaces of the raw multilayer body chip are applied with an electrically conductive paste for external electrode, which contains Ni as the first metal component, Sn as the second metal component, BaTiO3 and the like as ceramic particles (a ceramic material), a solvent, a dispersing agent, and the like. In this case, the amounts of Ni as the first metal component, Sn as the second metal component, and BaTiO3 and the like as ceramic particles (a ceramic material) that are contained in the electrically conductive paste for external electrode are adjusted such that the content of Sn is set at about 0.001 mol or more and about 0.1 mol or less, for example, assuming that the sum of Ni as the first metal component and Sn as the second metal component is 100 mol, and also such that the content of the ceramic material is set at about 5% or more and about 50% or less, for example, with respect to the entire volume of the underlying electrode layer.
- Then, the raw multilayer body chip and the electrically conductive paste for external electrode applied to the raw multilayer body chip are simultaneously baked to thus form a multilayer body including a baked layer formed as an underlying electrode layer.
- Then, a
plating layer 30 is formed on the surface of the underlying electrode layer. In the multilayer ceramic capacitor shown inFIG. 1 , the plating layer is formed to include a Cu plating layer as a lower plating layer, an Ni plating layer as an intermediate plating layer, and an Sn plating layer as an upper plating layer. - In the manner as described above, multilayer
ceramic capacitor 10 shown inFIG. 1 is manufactured. - Then, a multilayer ceramic capacitor was manufactured to conduct a moisture resistance reliability test in order to check the advantageous effects of the above-described multilayer ceramic capacitor according to the present invention.
- First, according to the above-described method of manufacturing a multilayer ceramic capacitor, multilayer ceramic capacitors according to Examples under the following specifications were produced.
-
-
- Structure of multilayer ceramic capacitor: two terminals (see
FIG. 1 ) - Dimensions L×W×T of multilayer ceramic capacitor (including design values): about 1.0 mm×about 0.5 mm×about 0.5 mm
- Materials of the dielectric layer: BaTiO3
- Capacitance: about 22 μF
- Rated voltage: about 4V
- Structure of internal electrode
- Third metal component: Ni
- Fourth metal component: none
- Structure of external electrode
- Underlying electrode layer
- First metal component: Ni
- Second metal component: Sn
- Content of second metal component: Sn/(Ni+Sn)=about 0.005 mol
- Ceramic material in underlying electrode layer: BaTiO3
- Content of ceramic material in underlying electrode layer: about 10%
- Plating layer: a three-layer structure including a Cu plating layer, an Ni plating layer, and an Sn plating layer
- Thickness of Cu plating layer: about 6 μm
- Thickness of Ni plating layer: about 4 μm
- Thickness of Sn plating layer: about 4 μm
- Structure of multilayer ceramic capacitor: two terminals (see
-
-
- Structure of multilayer ceramic capacitor: three terminals (see
FIG. 8 ) - Dimensions L×W×T of multilayer ceramic capacitor (including design values): about 1.0 mm×about 0.5 mm×about 0.5 mm
- Material of dielectric layer: BaTiO3
- Capacitance: about 15 μF
- Rated voltage: about 4V
- Structure of internal electrode
- Third metal component: Ni
- Fourth metal component: none
- Structure of external electrode
- Underlying electrode layer
- First metal component: Ni
- Second metal component: Sn
- Content of second metal component: Sn/(Ni+Sn)=about 0.005 mol
- Ceramic material in underlying electrode layer: BaTiO3
- Content of ceramic material in underlying electrode layer: about 10%
- Plating layer: a three-layer structure including a Cu plating layer, an Ni plating layer, and an Sn plating layer
- Thickness of Cu plating layer: about 6 μm
- Thickness of Ni plating layer: about 4 μm
- Thickness of Sn plating layer: about 4 μm
- Structure of multilayer ceramic capacitor: three terminals (see
- Then, multilayer ceramic capacitors according to Comparative Examples under the following specifications were produced.
- A multilayer ceramic capacitor according to Comparative Example 1 is the same or substantially the same as the multilayer ceramic capacitor in Example 1, except that the underlying electrode layer does not contain Sn. The specifications will be hereinafter described in detail.
-
- Structure of multilayer ceramic capacitor: two terminals
- Dimensions L×W×T of multilayer ceramic capacitor (including design values): about 1.0 mm×about 0.5 mm×about 0.5 mm
- Material of dielectric layer: BaTiO3
- Capacitance: 22 μF
- Rated voltage: 4V
- Structure of internal electrode
- Third metal component: Ni
- Fourth metal component: none
- Structure of external electrode
- Underlying electrode layer
- First metal component: Ni
- Second metal component: none
- Content of second metal component: none
- Ceramic material in underlying electrode layer: BaTiO3
- Content of ceramic material in underlying electrode layer: about 10%
- Plating layer: a three-layer structure including a Cu plating layer, an Ni plating layer, and an Sn plating layer
- Thickness of Cu plating layer: about 6 μm
- Thickness of Ni plating layer: about 4 μm
- Thickness of Sn plating layer: and 4 μm
- A multilayer ceramic capacitor according to Comparative Example 2 is the same or substantially the same as the multilayer ceramic capacitor in Example 2, except that the underlying electrode layer does not contain Sn. The specifications will be hereinafter described in detail.
-
- Structure of multilayer ceramic capacitor: three terminals
- Dimensions L×W×T of multilayer ceramic capacitor (including design values): about 1.0 mm×about 0.5 mm×about 0.5 mm
- Material of dielectric layer: BaTiO3
- Capacitance: 15 μF
- Rated voltage: 4V
- Structure of internal electrode
- Third metal component: Ni
- Fourth metal component: none
- Structure of external electrode
- Underlying electrode layer
- First metal component: Ni
- Second metal component: none
- Content of second metal component: none
- Ceramic material in underlying electrode layer: BaTiO3
- Content of ceramic material in underlying electrode layer: about 10%
- Plating layer: a three-layer structure including a Cu plating layer, an Ni plating layer, and an Sn plating layer
- Thickness of Cu plating layer: about 6 μm
- Thickness of Ni plating layer: about 4 μm
- Thickness of Sn plating layer: about 4 μm
- In this case, ten samples of each Example and ten samples of each Comparative Example were mounted on a glass-epoxy substrate with eutectic solder. Then, insulation resistance values of these samples were measured. Then, the glass-epoxy substrate was placed in a high-temperature high-humidity bath, in which a voltage of about 3.2 V was applied to each sample for about 72 hours in an environment of about 125° C. and a relative humidity of about 95% RH. After the moisture resistance reliability test, the insulation resistance values of the samples were measured.
- Then, the insulation resistance values of the samples were compared before and after the moisture resistance reliability test. Then, any sample showing an insulation resistance value decreased by one or more orders of magnitude was rated as defective and counted.
- Evaluation results are shown in Table 1.
-
TABLE 1 Number of Defectives Observed in Moisture Resistance Reliability Test (Pieces) Example 1 0/10 Example 2 0/10 Comparative Example 1 10/10 Comparative Example 2 10/10 - As shown in Table 1, in each of multilayer ceramic capacitors as samples in Examples 1 and 2, the underlying electrode layer of the external electrode contains Ni as the first metal component that is a main component and Sn as the second metal component that is a sub-component. Thus, due to progress of densification of the fired external electrode, none of ten samples was rated as defective in the result of the moisture resistance reliability test.
- In contrast, in each of the multilayer ceramic capacitors as samples in Comparative Examples 1 and 2, the underlying electrode layer of the external electrode contained only Ni as the first metal component but did not contain Sn as the second metal component that is a sub-component. Consequently, densification of the fired external electrode did not progress, and thus, all ten samples were rated as defective in the result of the moisture resistance reliability test.
- In view of the above, the following is can be understood. Specifically, the underlying electrode layer of the external electrode contains Ni as the first metal component that is a main component and Sn as the second metal component that is a sub-component. Thus, Ni and Sn are partially alloyed in the underlying electrode layer, and therefore, the melting point is lowered. Accordingly, the sinterability of the underlying electrode layer is improved to thus activate the reaction of the alloy in the underlying electrode layer, and thus, densification of the external electrode progresses, with the result that formation of gaps that may occur in the underlying electrode layer is reduced or prevented. This enables reduction or prevention of occurrence of gaps through which moisture infiltrates during formation of a plating layer and the like, and thus, moisture does not infiltrate into each external electrode, so that moisture can be prevented from infiltrating also into the multilayer body. Consequently, insulation deterioration in the multilayer ceramic capacitor can be prevented. As a result, it was clarified that the multilayer ceramic capacitor can be improved in reliability.
- While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
Claims (17)
1. A multilayer ceramic electronic component comprising:
a multilayer body including a plurality of first and second ceramic layers that are stacked, a first main surface and a second main surface that face each other in a height direction, a first side surface and a second side surface that face each other in a width direction orthogonal or substantially orthogonal to the height direction, and a first end surface and a second end surface that face each other in a length direction orthogonal or substantially orthogonal to the height direction and the width direction;
a first internal electrode layer on each of the first ceramic layers and exposed on the first end surface;
a second internal electrode layer on each of the second ceramic layers and exposed on at least one surface of the second end surface, the first side surface, and the second side surface;
a first external electrode connected to the first internal electrode layer and disposed on the first end surface; and
a second external electrode connected to the second internal electrode layer and disposed on the at least one surface on which the second internal electrode layer is exposed;
wherein the first external electrode includes a first underlying electrode layer;
the second external electrode includes a second underlying electrode layer; and
each of the first and second underlying electrode layers includes an alloy portion that includes an alloyed Ni as a first metal component and an alloyed Sn as a second metal component.
2. The multilayer ceramic electronic component according to claim 1 , wherein the first internal electrode layer includes Ni as a third metal component and an Sn material as a fourth metal component.
3. The multilayer ceramic electronic component according to claim 1 , wherein the second internal electrode layer includes Ni as a third metal component and an Sn material as a fourth metal component.
4. The multilayer ceramic electronic component according to claim 1 , wherein the first internal electrode layer includes a portion including an alloyed Ni as a third metal component and an alloyed Sn material as a fourth metal component.
5. The multilayer ceramic electronic component according to claim 1 , wherein the second internal electrode layer includes a portion including an alloyed Ni as a third metal component and an alloyed Sn material as a fourth metal component.
6. The multilayer ceramic electronic component according to claim 2 , wherein the first internal electrode layer includes a portion including an alloyed Ni defining the third metal component and an alloyed Sn material defining the fourth metal component.
7. The multilayer ceramic electronic component according to claim 3 , wherein the second internal electrode layer includes a portion including an alloyed Ni defining the third metal component and an alloyed Sn material defining the fourth metal component.
8. The multilayer ceramic electronic component according to claim 2 , wherein the Ni as the third metal component is a main component of the first internal electrode layer, and the Sn material as the fourth metal component is a sub-component of the first internal electrode layer.
9. The multilayer ceramic electronic component according to claim 3 , wherein the Ni as the third metal component is a main component of the second internal electrode layer, and the Sn material as the fourth metal component is a sub-component of the second internal electrode layer.
10. The multilayer ceramic electronic component according to claim 2 , wherein
a sum of the Ni as the third metal component and the Sn material as the fourth metal component is about 100 mol; and
a content of the Sn material is about 0.001 mol or more and about 0.1 mol or less.
11. The multilayer ceramic electronic component according to claim 3 , wherein
a sum of the Ni as the third metal component and the Sn material as the fourth metal component is about 100 mol; and
a content of the Sn material is about 0.001 mol or more and about 0.1 mol or less.
12. The multilayer ceramic electronic component according to claim 4 , wherein the portion of the first internal electrode layer including the alloyed Ni as the third metal component and the alloyed Sn material as the fourth metal component includes an alloy layer.
13. The multilayer ceramic electronic component according to claim 5 , wherein the portion of the second internal electrode layer including the alloyed Ni as the third metal component and the alloyed Sn material as the fourth metal component includes an alloy layer.
14. The multilayer ceramic electronic component according to claim 12 , wherein the alloy layer of the first internal electrode layer covers the first internal electrode layer.
15. The multilayer ceramic electronic component according to claim 13 , wherein the alloy layer of the second internal electrode layer covers the second internal electrode layer.
16. The multilayer ceramic electronic component according to claim 4 , wherein the portion of the first internal electrode layer including the alloyed Ni as the third metal component and the alloyed Sn material as the fourth metal component includes an end surface alloy layer at the interface between the first underlying electrode layer and the multilayer body.
17. The multilayer ceramic electronic component according to claim 5 , wherein the portion of the second internal electrode layer including the alloyed Ni as the third metal component and the alloyed Sn material as the fourth metal component includes an end surface alloy layer at the interface between the second underlying electrode layer and the multilayer body.
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